tag:theconversation.com,2011:/africa/topics/placenta-15977/articlesPlacenta – The Conversation2023-09-18T20:01:57Ztag:theconversation.com,2011:article/2073232023-09-18T20:01:57Z2023-09-18T20:01:57ZHow a 16th century Italian anatomist came up with the word ‘placenta’: it reminded him of a cake<figure><img src="https://images.theconversation.com/files/531045/original/file-20230609-15-lw1nva.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C878%2C935&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The placenta and umbilical cord. Watercolour image, unknown artist, 19th century.</span> <span class="attribution"><a class="source" href="https://wellcomecollection.org/works/n4d6wddp">Wellcome Collection</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>Ever wondered where the placenta got its name?</p>
<p>In Italy in the 1500s, the anatomist Matteo Realdo Colombo coined this term to describe the large fleshy organ of pregnancy. Colombo chose placenta because it resembled another big, round object seen in daily life: a cake.</p>
<p>In the premodern world, there existed a variety of words and concepts used to understand the placenta. </p>
<p>In <a href="https://www.journals.uchicago.edu/doi/full/10.1086/724867">my research</a>, I try to uncover the cultural significance of the placenta and afterbirth in premodern Europe (1500–1800) to help us better understand the social and medical history of this important organ.</p>
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<p>
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<strong>
Read more:
<a href="https://theconversation.com/explainer-what-is-placenta-28851">Explainer: what is placenta?</a>
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</em>
</p>
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<h2>Afterbirths and secundines</h2>
<p>Before the anatomical term placenta appeared, men and women in medieval Europe used the terms “afterbirth” (<em>nachgeburt</em> in German, <em>arrière-faix</em> in French) and “the second” (<em>secundina</em> in Italian, <em>secondine</em> in English). </p>
<p>These terms captured the fact that placental expulsion was the “second” part of a childbirth, necessary to end the birth. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/531040/original/file-20230608-14786-m63chi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A woodcut depicts a woman who has just recently finished giving birth being attended by various midwives" src="https://images.theconversation.com/files/531040/original/file-20230608-14786-m63chi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/531040/original/file-20230608-14786-m63chi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=586&fit=crop&dpr=1 600w, https://images.theconversation.com/files/531040/original/file-20230608-14786-m63chi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=586&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/531040/original/file-20230608-14786-m63chi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=586&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/531040/original/file-20230608-14786-m63chi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=736&fit=crop&dpr=1 754w, https://images.theconversation.com/files/531040/original/file-20230608-14786-m63chi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=736&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/531040/original/file-20230608-14786-m63chi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=736&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Illustrations from this 1850 obstetrical book by Jacobus Rueff show scenes of childbirth in 16th century Europe.</span>
<span class="attribution"><a class="source" href="https://wellcomecollection.org/works/jjcba979">Wellcome Library</a></span>
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<p>From the medieval to late early modern period, childbirth was very much the preserve of women midwives, family members and neighbours. Much of their knowledge about the placenta was transmitted orally (women were generally not literate, unless elite) yet some of this knowledge <a href="https://blogs.bl.uk/digitisedmanuscripts/2018/03/call-the-medieval-midwife.html">survives in texts</a>. </p>
<p>Male physicians recorded women’s knowledge about childbirth to demonstrate they could access “secret” knowledge about women’s bodies. This boosted their reputation among other male physicians, and gave credibility to their expertise over women’s health and childbirth.</p>
<p>One example of this is the 12th century medical compendium, <a href="https://en.wikipedia.org/wiki/Trotula">The Trotula</a>, one of the most influential works on women’s medicine in Europe from its publication until well into the 1500s. </p>
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<a href="https://images.theconversation.com/files/531035/original/file-20230608-11102-9xg2l3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A figure of a woman is painted in a manuscript on women's medicine" src="https://images.theconversation.com/files/531035/original/file-20230608-11102-9xg2l3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/531035/original/file-20230608-11102-9xg2l3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=843&fit=crop&dpr=1 600w, https://images.theconversation.com/files/531035/original/file-20230608-11102-9xg2l3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=843&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/531035/original/file-20230608-11102-9xg2l3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=843&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/531035/original/file-20230608-11102-9xg2l3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1059&fit=crop&dpr=1 754w, https://images.theconversation.com/files/531035/original/file-20230608-11102-9xg2l3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1059&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/531035/original/file-20230608-11102-9xg2l3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1059&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Trotula of Salerno.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Trotula_of_Salerno.jpg">Wikimedia Commons</a></span>
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<p>The text, a compilation of different medical treatises, was supposedly authored by the first female physician and professor, Trota, in Salerno, Italy. </p>
<p>Although modern scholars suggest that some of the text’s authors were certainly male, <a href="https://www.youtube.com/watch?v=v1iRJJT403o">historian Monica Green</a> argues that part of the work was likely shaped by a female midwife or healer, possibly called Trota. </p>
<p>At this time, there were many female healers in Salerno, and it was typically only women who had access to women’s births and bodies.</p>
<p>Examining The Trotula allows us to see earlier cultural and medical ideas about the placenta. The author describes how, during birth: </p>
<blockquote>
<p>The foetus is expelled from its bed, that is to say the afterbirth, by the force of Nature.</p>
</blockquote>
<p>The afterbirth and foetus were understood as having a close, companion-like relationship; the placenta was a “bed” for the foetus during pregnancy, providing support and comfort.</p>
<p>We can also see how the afterbirth might be used following pregnancy and birth. Trota writes:</p>
<blockquote>
<p>If [the mother] has been badly torn in birth and afterward for fear of death does not wish to conceive any more, let her put into the afterbirth as many grains of caper spurge or barley as the number of years she wishes to remain barren.</p>
</blockquote>
<p>The post-birth use of the placenta in remedies was common in Europe. The afterbirth was perceived as having “sympathetic” healing qualities relating to future fertility and the health of the infant. </p>
<h2>Anatomy and the afterbirth: new terms</h2>
<p>Women’s ideas about placental remedies were often ridiculed by university-educated male anatomists, who labelled these practices “superstitious”. Yet, many did respect women’s knowledge as experts in childbirth. </p>
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<a href="https://images.theconversation.com/files/531036/original/file-20230608-23-vl0v79.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="The image depicts an anatomical theatre in which many men surround an anatomical table. In the centre above the table colombo is dissecting a man's corpse and showing organs to the students." src="https://images.theconversation.com/files/531036/original/file-20230608-23-vl0v79.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/531036/original/file-20230608-23-vl0v79.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=847&fit=crop&dpr=1 600w, https://images.theconversation.com/files/531036/original/file-20230608-23-vl0v79.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=847&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/531036/original/file-20230608-23-vl0v79.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=847&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/531036/original/file-20230608-23-vl0v79.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1064&fit=crop&dpr=1 754w, https://images.theconversation.com/files/531036/original/file-20230608-23-vl0v79.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1064&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/531036/original/file-20230608-23-vl0v79.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1064&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">De Re Anatomica (1559), frontispiece.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:De_re_anatomica_libri_XV,_Realdo_Colombo,_1559_Wellcome_L0000134.jpg">Wikimedia Commons</a></span>
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<p>When Italian anatomist Matteo Realdo Colombo coined the term “placenta” in the 16th century, he used a term directly related to women’s worlds: cooking. Colombo was professor of anatomy at the University of Padua, a hub for <a href="https://www.unipd.it/en/palazzo-bo-and-anatomical-theatre">anatomical learning</a> in Europe at the time.</p>
<p>Colombo described the shape and function of the human placenta in his anatomical treatise, <em>De Re Anatomica</em> (On Things Anatomical, 1559). </p>
<p>In this book, Colombo introduced the term “placenta” to distinguish it from other anatomical terms, as well as midwifery terms like “secundina”. </p>
<p>“Placenta” referred to a wide, flat cake, cooked in a pan with layers of cheese and honey, dating <a href="https://www.google.com.au/books/edition/M_Porci_Catonis_De_Agricultura_Sive_De_R/MamGBIYAMdIC?hl=en&gbpv=1">as far back</a> as Ancient Rome.</p>
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<p>Colombo chose this term to describe the large, flat organ, “circular” like a placenta cake, and of a similar size. </p>
<p>In choosing the term placenta, he also associated the organ with ideas about women’s worlds, of cooking and childbirth; the placenta, like the Italian cake, provided nourishment and comfort. This idea connected with earlier ones like the Trotula, which suggested the afterbirth was the foetus’ bed.</p>
<h2>The placenta today</h2>
<p>Exploring the history of ideas about the placenta and afterbirth offer us insights into how people have valued this important organ. </p>
<p>This can tell us about the development of scientific knowledge, such as the emergence of the word placenta, providing context for <a href="https://www.sciencedirect.com/science/article/pii/S0143400414000861">urgent placental science</a> being undertaken today. History can help us determine how and why in different times and cultures, science has or has not prioritised placental research.</p>
<p>Histories of the placenta also help provide context for current cultural attitudes to and practices around the afterbirth, such as <a href="https://theconversation.com/no-you-shouldnt-eat-your-placenta-heres-why-86405">eating the placenta</a> and turning the placenta into <a href="https://midwifebalance.com.au/placenta-encapsulation/pricing/">memorabilia, jewellery or art</a>.</p>
<p>By studying past knowledge about the placenta, we can see the echoes of attitudes to this organ in our modern science and culture. </p>
<p>Our bodies are not static. They are deeply shaped by the prevailing medical and cultural perceptions of our times. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/no-you-shouldnt-eat-your-placenta-heres-why-86405">No, you shouldn't eat your placenta, here's why</a>
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</em>
</p>
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<img src="https://counter.theconversation.com/content/207323/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Paige Donaghy does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>In my research, I try to uncover the cultural significance of the placenta and afterbirth in premodern Europe to help us better understand the social and medical history of this important organ.Paige Donaghy, Early career researcher, The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2054772023-08-18T02:08:23Z2023-08-18T02:08:23ZCurious Kids: why do babies cry when they come out of their mum?<figure><img src="https://images.theconversation.com/files/543119/original/file-20230816-21-5r1861.jpg?ixlib=rb-1.1.0&rect=2%2C0%2C995%2C664&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/newborn-baby-78559918">Shutterstock</a></span></figcaption></figure><blockquote>
<p>Why do babies always cry when they come out of their mum? – Nam, 12, Hanoi, Vietnam</p>
</blockquote>
<p><a href="https://theconversation.com/au/topics/curious-kids-36782"><img src="https://images.theconversation.com/files/291898/original/file-20190911-190031-enlxbk.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=90&fit=crop&dpr=1" width="100%"></a></p>
<p>When babies are born, they all seem to cry. We see this a lot <a href="https://www.goldderby.com/gallery/best-tv-births-ranked-worst-to-best/tvs-most-memorable-births-little-house-ont-the-prarie/">on TV</a>.</p>
<p>But not all newborn babies cry straight away. Here’s what’s going on.</p>
<h2>What happens at birth?</h2>
<p>When a baby is born, they move from their mum’s warm body, and out of their dark, watery world into a much cooler, drier and brighter one.</p>
<p>It’s a bit of a squeeze. As the baby comes out from their mum, the cooler air hits their wet skin. </p>
<p>The cooler air makes them gasp. They also gasp when the midwife or doctor touches their body to help them come into the world.</p>
<p>That gasp is their first breath, which usually comes with a cry. And when this happens the gasp or cry triggers an amazing <a href="https://www.youtube.com/watch?v=zTXmaVgobNw">change</a> in how the baby gets oxygen and moves it around their body.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-why-do-we-cry-119814">Curious Kids: why do we cry?</a>
</strong>
</em>
</p>
<hr>
<h2>What changes?</h2>
<p>In the womb, babies depend on their mum for oxygen – via the <a href="https://theconversation.com/explainer-what-is-placenta-28851">placenta</a> and <a href="https://theconversation.com/ive-always-wondered-whats-behind-the-belly-button-84598">umbilical cord</a>.</p>
<p>The placenta looks a bit like a pancake and filters oxygen-rich blood from the mum. The umbilical cord then pumps that to the unborn baby.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/543140/original/file-20230817-17-84peqv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Unborn baby with umbilical cord and placenta" src="https://images.theconversation.com/files/543140/original/file-20230817-17-84peqv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/543140/original/file-20230817-17-84peqv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/543140/original/file-20230817-17-84peqv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/543140/original/file-20230817-17-84peqv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/543140/original/file-20230817-17-84peqv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/543140/original/file-20230817-17-84peqv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/543140/original/file-20230817-17-84peqv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The placenta, on the left, and the umbilical cord work together to send oxygen from the mum’s blood to the unborn baby.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/3d-rendered-medically-accurate-illustration-fetus-727111807">Shutterstock</a></span>
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<p>But once babies are born, their first breath or cry triggers a whole range of changes to the way their heart moves blood around their body. So, rather than breathing fluid from the womb, they can now breathe air and get oxygen into their lungs just like we do. </p>
<p>The process of being born also squeezes water out of the baby’s lungs, allowing them to work properly.</p>
<p>A newborn baby crying is a sound parents and health workers are very <a href="https://www.romper.com/p/why-do-babies-cry-at-birth-the-answer-will-probably-surprise-you-18746386">happy</a> to hear. That’s because it usually means the baby is well and won’t need any extra help to breathe.</p>
<p>But not all newborn babies cry. And it’s not always something to be worried about.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-is-it-true-that-male-seahorses-give-birth-92843">Curious Kids: Is it true that male seahorses give birth?</a>
</strong>
</em>
</p>
<hr>
<h2>Why don’t all babies cry?</h2>
<p>Sometimes this switch to moving oxygen around the body just like us <a href="https://www.hopkinsmedicine.org/health/conditions-and-diseases/persistent-pulmonary-hypertension#:%7E:text=In%20persistent%20pulmonary%20hypertension%2C%20also,difficult%20birth%2C%20or%20birth%20asphyxia.">does not happen smoothly</a>.</p>
<p>There might be problems with the baby’s heart, or there may have been a difficult birth. For instance, the baby might have been very short of oxygen in the womb and need some help to start breathing when they are born. </p>
<p>Sometimes there’s a delay in babies crying. </p>
<p>Babies born by caesarean section – when doctors operate on the mum to lift the baby out of her womb – might be <a href="https://link.springer.com/article/10.1007/s00404-019-05208-7">slower</a> to breathe and cry. That’s because they don’t have the fluid squeezed from the lungs like they do when born through the vagina. </p>
<p>Sometimes newborn babies don’t cry at all.</p>
<p>Babies born in water (known as a <a href="https://www.bellybelly.com.au/birth/doulas/preparing-for-a-water-birth/">waterbirth</a>) may have lots of warm water around them and not even realise they are born. That’s because they don’t feel cold air as they come into the world; they are often in their mother’s arms in the water. So they tend to just <a href="https://www.sarawickham.com/questions-and-answers/whats-an-aqua-apgar/">breathe quietly</a>, and turn pink (showing they are getting enough oxygen), without crying.</p>
<hr>
<p><em>Hello, Curious Kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to curiouskids@theconversation.edu.au</em></p><img src="https://counter.theconversation.com/content/205477/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Hannah Dahlen receives funding from NHMRC and ARC. She is affiliated with The Australian College of Midwives</span></em></p>Crying triggers changes in how a newborn baby gets their oxygen. But not all new babies cry, and it’s not always a problem.Hannah Dahlen, Professor of Midwifery, Associate Dean Research and HDR, Midwifery Discipline Leader, Western Sydney UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1983592023-01-25T17:48:50Z2023-01-25T17:48:50ZClaims that foetuses are surrounded by bacteria in the womb are incorrect – new review<figure><img src="https://images.theconversation.com/files/506341/original/file-20230125-22-cubf7x.jpg?ixlib=rb-1.1.0&rect=0%2C6%2C4012%2C3129&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Turns out it is a sterile environment after all.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/happy-couple-pregnancy-news-1082692088">Rawpixel/Shutterstock</a></span></figcaption></figure><p>When a baby is born, its immune system is already developed to survive in a world full of germs. This developmental process is not only important for the baby but also for lifelong health. However, our understanding of the process is vastly incomplete. Specifically, scientists do not agree on when the foetus is first exposed to microbes. </p>
<p>Historically, the scientific view was that the foetus, as well as the womb in which the foetus grows, including the placenta and the amniotic fluid (the liquid surrounding the foetus), are sterile. Yet since the arrival of DNA sequencing, several research groups found evidence for microbial communities in the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4929217/">placenta</a> and <a href="https://www.frontiersin.org/articles/10.3389/fmicb.2019.01124/full#:%7E:text=The%20amniotic%20fluid%20microbiome%20was,those%20previously%20reported%20in%20infants.">amniotic fluid</a>. </p>
<p>Some scientists suggested that these microbiomes (communities of bacteria, fungi and viruses) are part of a natural pregnancy and that they expose the foetus to live microbes that prime its immune system. But a new review published in <a href="https://www.nature.com/articles/s41586-022-05546-8">Nature</a>, involving myself and an international team of 45 other experts, has found no sound evidence for such a microbiome.</p>
<p>An entire research field has grown up around this area that goes beyond the description of supposed microbial communities in the womb and into <a href="https://www.frontiersin.org/articles/10.3389/fcimb.2020.00413/full">speculation on their potential medical importance</a>. Tens of millions of euros have been spent researching this and hundreds of papers published.</p>
<p>Not all scientists have shared the excitement, though. Counter arguments were put forward <a href="https://phylogenomics.me/2014/05/23/overselling-the-microbiome-award-many-for-stories-about-placental-vs-oral-microbiomes/">quite early on</a> that a foetal microbiome would not be possible because of <a href="https://microbiomejournal.biomedcentral.com/articles/10.1186/s40168-017-0268-4">what we know about human biology</a>. </p>
<p>For example, we know that the placenta is full of anatomical and immunological barriers that prevent microbes from entering and colonising it. We also know that the foetus’s developing immune system would be unable to control the microbes.</p>
<p>Scepticism was supported by an increasing number of studies which showed that the microbial DNA detected in the placenta and amniotic fluid was due to contamination of the samples, research devices, and the reagents (chemical ingredients) used to isolate the DNA from the samples. </p>
<p><a href="https://www.theatlantic.com/science/archive/2019/07/placental-microbiome-should-be-cautionary-tale/595114/">A lively scientific debate</a> arose with views that were pretty much irreconcilable. The controversy culminated when four studies, published in 2020 and 2021 in respected scientific journals, studied the microbes in the human foetus directly through DNA sequencing and came to opposite conclusions. </p>
<p>Two found viable microbial populations in the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8110246/">intestines</a> and <a href="https://www.sciencedirect.com/science/article/pii/S0092867421005742">organs</a> of vaginally delivered foetuses and linked these microbes to the development of the immune system. The <a href="https://www.nature.com/articles/s41564-021-00904-0">other</a> <a href="https://insight.jci.org/articles/view/138751">two</a> reported no evidence for microbes. </p>
<p>Such uncertainties on a fundamental issue pose a substantial challenge for scientific progress, for example, by diverting finite resources into research that results in no advancement for the health of babies and their mothers. There is also the risk of misguided attempts to therapeutically modify microbiomes that don’t exist. </p>
<p>To resolve the debate, our team assessed the evidence and reviewed all aspects of the contradictory data. Given the controversy, we aimed to approach the problem from different angles. We included experts in all the scientific disciplines important to the debate, specifically reproductive biology, microbiology, data science, immunology, clinical microbiology and gnotobiology (the study of germ-free plants and animals). We were interested in a balanced approach, so more than half of the scientists involved had no previous involvement in the debate. </p>
<figure class="align-center ">
<img alt="Mother holding her baby" src="https://images.theconversation.com/files/506376/original/file-20230125-16-swh0s3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/506376/original/file-20230125-16-swh0s3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/506376/original/file-20230125-16-swh0s3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/506376/original/file-20230125-16-swh0s3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/506376/original/file-20230125-16-swh0s3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/506376/original/file-20230125-16-swh0s3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/506376/original/file-20230125-16-swh0s3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Scientists have been divided about when a baby first encounters microbes – in the womb or during birth?</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/mother-holding-her-newborn-baby-child-584787691">Natalia Deriabina/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Unanimously refuted</h2>
<p>The team unanimously refuted the concept of a foetal microbiome and concluded that the detection of microbes in foetal tissues was due to contamination of samples drawn from the womb, reagents or research devices. </p>
<p>A systematic comparison of the bacterial communities detected in foetuses delivered vaginally versus through caesarean section established that most contamination occurred during vaginal sampling. The experts further concluded that the existence of live microbes in healthy foetal tissues is not compatible with fundamental concepts of reproductive biology, immunology, clinical microbiology, and the ability to derive germ-free mammals.</p>
<p>We are hopeful that the consensus among the experts we assembled provides guidance for future research. It establishes a solid scientific foundation to concentrate research efforts where they will be most effective. </p>
<p>It is still important to discover how the immune system of the foetus develops. But knowing that the foetus is sterile shifts the emphasis away from live microbes towards the cell components of microbes and the chemicals (metabolites) they produce. Such compounds have been shown to cross the placenta to prepare the foetus’s immune system for life in a germ-filled world. </p>
<p>Our new paper clarifies that babies are colonised by microbes during birth and thereafter. Efforts to modulate microbiomes to improve infant and lifelong health should therefore be focused on the period after birth.</p><img src="https://counter.theconversation.com/content/198359/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jens Walter receives funding from by Science Foundation Ireland (SFI) through a Centre award (APC/SFI/12/RC/2273_P2) to APC Microbiome Ireland and an SFI Professorship (19/RP/6853)</span></em></p>Some scientists believe that the placenta and amniotic fluid that surrounds a foetus have their own microbiome. A new review refutes this.Jens Walter, Professor at the School of Microbiology, University College CorkLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1938072022-11-30T13:39:31Z2022-11-30T13:39:31ZPregnancy is a genetic battlefield – how conflicts of interest pit mom’s and dad’s genes against each other<figure><img src="https://images.theconversation.com/files/497774/original/file-20221128-20372-q68nv3.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2059%2C1454&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Paternal and maternal genes drive fetal development in different directions.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/hacking-baby-embryo-decoding-the-dna-of-royalty-free-illustration/1125420175">Valentina Kruchinina/iStock via Getty Images</a></span></figcaption></figure><p>Baby showers. Babymoons. Baby-arrival parties. There are many opportunities to celebrate the 40-week transition to parenthood. Often, these celebrations implicitly assume that pregnancy is cooperative and mutually beneficial to both the parent and the fetus. But this belief obscures a more interesting truth about pregnancy – the mother and the fetus may not be peacefully coexisting in the same body at all.</p>
<p>At the most fundamental level, there is a conflict between the interests of the parent and fetus. While this may sound like the beginning of a thriller, this <a href="https://doi.org/10.1086/418300">genetic conflict</a> is a normal part of pregnancy, leading to typical growth and development both during pregnancy and across an individual’s lifetime – something <a href="https://scholar.google.com/citations?user=YBPxHqkAAAAJ&hl=en&oi=ao">my research</a> focuses on. </p>
<p>However, even though genetic conflict is normal during pregnancy, it can play a role in pregnancy complications and developmental disorders when left unchecked.</p>
<h2>What is genetic conflict?</h2>
<p>Pregnancy is generally thought of as a period when a new individual is created from a unified blend of genes from their parents. But this is not quite right. </p>
<p>The genes a fetus gets from each parent carry slightly different instructions for development. This means there are contrasting and sometimes conflicting blueprints for how to build the new individual. Conflict over <a href="https://doi.org/10.1016/0168-9525(91)90230-N">which blueprint to follow</a> for fetal growth and development is the essence of the genetic conflict that occurs during pregnancy.</p>
<p>Moms have to use their bodies to help the fetus grow during pregnancy while dads don’t. This means that the genes the fetus inherits from mom have to not only provide for the current fetus, but also try to keep mom alive and healthy and make sure there are resources left over for a potential future pregnancy. These reserves include both biological resources like glucose, protein, iron and calcium, as well as the time and energy needed to help her children after birth as they grow and develop.</p>
<p>Dad’s genes don’t have this same pressure because they don’t use their bodies to help the fetus grow during pregnancy. A dad’s genes, then, don’t need to ensure that anyone other than the current fetus thrives.</p>
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<figcaption><span class="caption">Pregnancy transforms every organ in the body.</span></figcaption>
</figure>
<p>To better understand this situation, pretend that all of the resources a mom can give her children come in the form of a <a href="https://cir.nii.ac.jp/crid/1570854174915527168">milkshake</a>. Once the milkshake runs out, mom has nothing left to give her children. Maternal genes, therefore, want each child to drink only as much as they need to grow and develop. This ensures that the milkshake can be “shared” across all current and future children. </p>
<p>Paternal genes, on the other hand, have no such guarantee of representation in this mother’s other children – the father of the current child may not be the father of the mother’s potential future children. This lack of guaranteed genetic representation means there is no pressure on the father to “share” the milkshake. The best strategy when it comes to paternal genes, then, is for the fetus to drink as much of the milkshake as they can.</p>
<p>These two strategies play a figurative game of tug of war throughout pregnancy. Both sides are trying to pull fetal development slightly more toward their side. Paternal genes encourage the fetus to grow and develop quickly and take more resources, while maternal genes encourage the fetus to grow and use only what’s necessary for proper development. Conflict over how deeply the <a href="https://doi.org/10.1016/0168-9525(91)90230-N">embryo implants</a> in the uterus and how quickly the <a href="https://doi.org/10.1016/j.placenta.2012.05.002">placenta</a> and <a href="https://doi.org/10.1016/j.placenta.2005.07.004">fetus</a> grow are just a few areas where researchers have documented this tug of war during pregnancy.</p>
<p>The milkshake problem helps researchers determine where to look for genetic conflict by simplifying where trade-offs may take place during pregnancy. Because fetal growth is at the heart of genetic conflict, researchers have focused on processes where conflict over resource transfers from mother to fetus can be observed. These investigations have found that the placenta, a fetal organ responsible for all resource transfers during pregnancy, is <a href="https://www.hup.harvard.edu/catalog.php?isbn=9780674027220">dominated by paternally-expressed genes</a>. It releases paternally-derived <a href="https://doi.org/10.1038/ng0593-98">insulin-like growth factors</a> that make mom less sensitive to her own insulin and hormones that <a href="https://doi.org/10.1093/humrep/16.1.13">increase maternal blood pressure</a>, both of which ultimately increase the amount of resources the fetus can use to grow during pregnancy but have the potential to harm the mother’s health.</p>
<h2>Genetic conflict and pregnancy complications</h2>
<p>If genetic conflict goes uncontrolled, it can cause <a href="https://doi.org/10.1086/418300">pregnancy complications</a> for the mother and <a href="https://doi.org/10.1002/ajhb.10150">developmental disorders</a> for the child. In fact, there is a growing consensus among researchers that some of the most well-known pregnancy complications like <a href="https://doi.org/10.1126/science.1111726">preeclampsia</a>, <a href="https://doi.org/10.1007/978-3-319-19650-3_3044">gestational diabetes</a>, <a href="https://doi.org/10.1016/j.semcdb.2022.01.007">miscarriages</a> and <a href="https://doi.org/10.1093/aje/kwp325">preterm births</a> may best be explained by unchecked genetic conflict.</p>
<p>Despite the potential role that genetic conflict plays in pregnancy complications, current medical treatments are reactive rather than proactive. A pregnant person must <a href="https://www.mayoclinic.org/diseases-conditions/preeclampsia/diagnosis-treatment/drc-20355751">show signs of experiencing complications</a> before medical interventions and treatments can take place. </p>
<p>Knowing how unchecked genetic conflict contributes to pregnancy complications could provide researchers another way to develop treatments that are proactive and, ideally, preventive. However, there are currently no treatments for pregnancy complications that consider genetic conflict. Though <a href="https://doi.org/10.2337%2Fdb19-0798">gestational diabetes</a> can be attributed to underlying genetic conflict, a pregnant person must present with elevated blood sugar levels before doctors can treat underlying conflict over insulin production and blood sugar.</p>
<figure>
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<figcaption><span class="caption">Pregnancy during the COVID-19 pandemic has been challenging for many.</span></figcaption>
</figure>
<p>The experiences of pregnant people during the COVID-19 pandemic provide an example of why more research on genetic conflict is needed. During the pandemic, doctors saw both a dramatic decrease in the number of <a href="http://dx.doi.org/10.1136/archdischild-2020-319990">preterm births</a> as well as an increase in the number of <a href="https://doi.org/10.1001/jama.2020.12746">stillbirths and miscarriages</a>. Both types of complications are influenced by genetic conflict, but the reasons behind these opposing trends are unclear.</p>
<p>As a woman who was pregnant early in the pandemic, my pregnancy was scary and stressful, spent at home away from the pressures of “normal” life. More research on the complex process of pregnancy and genetic conflict’s role in complications could help researchers better understand how the changes brought by the pandemic produced such wildly different pregnancy outcomes.</p><img src="https://counter.theconversation.com/content/193807/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jessica D. Ayers does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Genetic conflict may play a role in pregnancy complications, such as preeclampsia and gestational diabetes, as well as developmental disorders.Jessica D. Ayers, Assistant Professor of Psychological Science, Boise State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1923222022-10-18T18:03:18Z2022-10-18T18:03:18ZHumans are 8% virus – how the ancient viral DNA in your genome plays a role in human disease and development<figure><img src="https://images.theconversation.com/files/489839/original/file-20221014-18-y4o10m.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2121%2C1412&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Pandemics over the course of evolution have led to the integration of viruses into our genome.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/three-dimensional-render-of-single-royalty-free-illustration/1249814587">Westend61via Getty Images</a></span></figcaption></figure><p>Remnants of ancient viral pandemics in the form of viral DNA sequences embedded in our genomes are still active in healthy people, according to <a href="http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3001826">new research</a> my <a href="https://scholar.google.com/citations?hl=en&user=AZcPXsIAAAAJ">colleagues</a> <a href="https://scholar.google.com/citations?user=pyRxplAAAAAJ&hl=en">and I</a> recently published.</p>
<p>HERVs, or human endogenous retroviruses, make up around <a href="https://doi.org/10.1038/35057062">8% of the human genome</a>, left behind as a result of infections that humanity’s primate ancestors suffered millions of years ago. They became part of the human genome due to how they replicate. </p>
<p>Like modern HIV, these ancient <a href="https://doi.org/10.1099%2Fjgv.0.001712">retroviruses</a> had to insert their genetic material into their host’s genome to replicate. Usually this kind of viral genetic material isn’t passed down from generation to generation. But some ancient retroviruses gained the ability to <a href="https://doi.org/10.1038/s41579-019-0189-2">infect germ cells</a>, such as egg or sperm, that do pass their DNA down to future generations. By targeting germ cells, these retroviruses became incorporated into human ancestral genomes over the course of millions of years and may have implications for how researchers screen and test for diseases today.</p>
<h2>Active viral genes in the human genome</h2>
<p>Viruses insert their genomes into their hosts in the form of a <a href="https://www.verywellhealth.com/provirus-hiv-glossary-definition-48962">provirus</a>. There are around <a href="https://doi.org/10.1186/1742-4690-2-50">30 different kinds</a> of human endogenous retroviruses in people today, amounting to over 60,000 proviruses in the human genome. They demonstrate the long history of the many pandemics humanity has been subjected to over the course of evolution. Scientists think these viruses once widely infected the population, since they have become fixed in not only the human genome but also in <a href="https://doi.org/10.1371%2Fjournal.pone.0101195">chimpanzee</a>, <a href="https://doi.org/10.1073/pnas.1814203116">gorilla</a> and other primate genomes.</p>
<p>Research from <a href="https://gsbs.tufts.edu/facultyResearch/faculty/coffin-john/research">our lab</a> and others has demonstrated that HERV genes are active in diseased tissue, such as <a href="https://doi.org/10.1128/JVI.01258-17">tumors</a>, as well as during <a href="https://doi.org/10.1016%2Fj.csbj.2021.10.037">human embryonic development</a>. But how active HERV genes are in healthy tissue was still largely unknown.</p>
<p>To answer this question, our lab decided to focus on one group of HERVs known as HML-2. This group is the <a href="https://doi.org/10.1186/1742-4690-8-90">most recently active of the HERVs</a>, having gone extinct less than 5 million years ago. Even now, some of its proviruses within the human genome still retain the ability to make viral proteins. </p>
<p>We examined the genetic material in a <a href="https://www.gtexportal.org/home/">database</a> containing over 14,000 donated tissue samples from all across the body. We looked for sequences that matched each HML-2 provirus in the genome and found 37 different HML-2 proviruses that were still active. All 54 tissue samples we analyzed had some evidence of activity of one or more of these proviruses. Furthermore, each tissue sample also contained genetic material from at least one provirus that could still produce viral proteins.</p>
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<figcaption><span class="caption">HERVs have influenced humans in ways researchers are still figuring out.</span></figcaption>
</figure>
<h2>The role of HERVs in human health and disease</h2>
<p>The fact that thousands of pieces of ancient viruses still exist in the human genome and can even create protein has drawn a considerable amount of attention from researchers, particularly since related viruses still active today can cause <a href="https://doi.org/10.3390%2Fv2092000">breast cancer</a> and <a href="https://doi.org/10.1111%2Fj.1600-0684.2010.00412.x">AIDS-like disease</a> in animals.</p>
<p>Whether the genetic remnants of human endogenous retroviruses can cause disease in people is still under study. Researchers have spotted viruslike particles from HML-2 <a href="https://doi.org/10.1006/viro.1993.1487">in cancer cells</a>, and the presence of HERV genetic material in diseased tissue has been associated with conditions such as <a href="https://doi.org/10.3390%2Fmicroorganisms9081784">Lou Gehrig’s disease, or amyotrophic lateral sclerosis</a>, as well as <a href="https://doi.org/10.1007/s12035-018-1255-x">multiple sclerosis</a> and even <a href="https://doi.org/10.3389%2Ffpsyt.2015.00183">schizophrenia</a>.</p>
<p>Our study adds a new angle to this data by showing that HERV genes are present even in healthy tissue. This means that the presence of HERV RNA may not be enough to connect the virus to a disease. </p>
<p>Importantly, it also means that HERV genes or proteins may no longer be good targets for drugs. HERVs have been explored as a target for a number of potential drugs, including <a href="https://doi.org/10.1186/s12977-017-0347-4">antiretroviral medication</a>, <a href="https://doi.org/10.1093/jnci/djr540">antibodies for breast cancer</a> and <a href="https://doi.org/10.1158/1078-0432.ccr-14-3197">T-cell therapies for melanoma</a>. Treatments using HERV genes as a cancer biomarker will also need to take into account their activity in healthy tissue.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/CDA1ISk0rlI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A developing fetus shares a few commonalities with viruses.</span></figcaption>
</figure>
<p>On the other hand, our research also suggests that HERVs could even be beneficial to people. The most famous HERV embedded in human and animal genomes, <a href="https://doi.org/10.1016/j.placenta.2012.05.005">syncytin</a>, is a gene derived from an ancient retrovirus that plays an important role in the formation of the placenta. Pregnancy in all mammals is dependent on the virus-derived protein coded in this gene. </p>
<p>Similarly, <a href="https://doi.org/10.1038/382826a0">mice</a>, <a href="https://doi.org/10.1128%2FJVI.01267-13">cats</a> and <a href="https://doi.org/10.1128%2FJVI.01859-06">sheep</a> also found a way to use endogenous retroviruses to protect themselves against the original ancient virus that created them. While these embedded viral genes are unable to use their host’s machinery to create a full virus, enough of their damaged pieces circulate in the body to interfere with the replication cycle of their ancestral virus if the host encounters it. Scientists theorize that <a href="https://doi.org/10.7554/elife.22519">one HERV</a> may have played this protective role in people millions of years ago. Our study highlights a few more HERVs that could have been claimed or co-opted by the human body much more recently for this same purpose.</p>
<h2>Unknowns remain</h2>
<p>Our research reveals a level of HERV activity in the human body that was previously unknown, raising as many questions as it answered. </p>
<p>There is still much to learn about the ancient viruses that linger in the human genome, including whether their presence is beneficial and what mechanism drives their activity. Seeing if any of these genes are actually made into proteins will also be important.</p>
<p>Answering these questions could reveal previously unknown functions for these ancient viral genes and better help researchers understand how the human body reacts to evolution alongside these vestiges of ancient pandemics.</p><img src="https://counter.theconversation.com/content/192322/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Aidan Burn receives funding from the National Cancer Institute. </span></em></p>Bits of viral genes incorporated into human DNA have been linked to cancer, ALS and schizophrenia. But many of these genes may not be harmful, and could even protect against infectious disease.Aidan Burn, PhD Candidate in Genetics, Tufts UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1675342021-09-16T02:17:54Z2021-09-16T02:17:54ZPregnant male seahorses support up to 1,000 growing babies by forming a placenta<figure><img src="https://images.theconversation.com/files/420378/original/file-20210910-17-lceud2.jpg?ixlib=rb-1.1.0&rect=0%2C1%2C1000%2C747&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Supplying oxygen to their growing offspring and removing carbon dioxide is a major challenge for every pregnant animal. Humans deal with this problem by developing a placenta, but in seahorses — where the male, not the female, gestates and gives birth to the young — exactly how it worked hasn’t always been so clear.</p>
<p>Male seahorses incubate their embryos inside a pouch, and until now it was unclear how the embryos “breathe” inside this closed structure. Our new study, published in the journal <a href="https://www.sciencedirect.com/science/article/abs/pii/S0143400421005816">Placenta</a>, examines how pregnant male seahorses (<em>Hippocampus abdominalis</em>) provide oxygen supply and carbon dioxide removal to their embryos.</p>
<p>We examined male seahorse pouches under the microscope at different stages of pregnancy, and found they develop complex placental structures over time — in similar ways to human pregnancy. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/419939/original/file-20210908-19-bemc8h.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/419939/original/file-20210908-19-bemc8h.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=402&fit=crop&dpr=1 600w, https://images.theconversation.com/files/419939/original/file-20210908-19-bemc8h.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=402&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/419939/original/file-20210908-19-bemc8h.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=402&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/419939/original/file-20210908-19-bemc8h.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=505&fit=crop&dpr=1 754w, https://images.theconversation.com/files/419939/original/file-20210908-19-bemc8h.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=505&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/419939/original/file-20210908-19-bemc8h.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=505&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Male pot-bellied seahorses have large fleshy pouches where embryos develop during pregnancy.</span>
<span class="attribution"><span class="source">by Aaron Gustafson</span></span>
</figcaption>
</figure>
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Read more:
<a href="https://theconversation.com/curious-kids-is-it-true-that-male-seahorses-give-birth-92843">Curious Kids: Is it true that male seahorses give birth?</a>
</strong>
</em>
</p>
<hr>
<h2>A pregnant dad gestating up to 1,000 babies</h2>
<p>Male pregnancy is rare, only occurring in a group of fish that includes seahorses, seadragons, pipehorses and pipefishes. </p>
<p>Pot-bellied seahorse males have a specialised enclosed structure on their tail. This organ is called the brood pouch, in which the <a href="https://theconversation.com/curious-kids-is-it-true-that-male-seahorses-give-birth-92843">embryos develop</a>.</p>
<p>The female deposits eggs into the male’s pouch after a <a href="https://www.youtube.com/watch?v=oa3lt7ewW9U">mating dance</a> and pregnancy lasts about <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.0022-1112.2004.00429.x">30 days</a>. </p>
<p>While inside the pouch, the male <a href="https://pubmed.ncbi.nlm.nih.gov/32617716/">supplies nutrients</a> to his developing embryos, before <a href="https://www.youtube.com/watch?v=b_nEA3dtOZs">giving birth</a> to up to 1,000 babies.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/419941/original/file-20210908-7120-1hsxjfw.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/419941/original/file-20210908-7120-1hsxjfw.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=512&fit=crop&dpr=1 600w, https://images.theconversation.com/files/419941/original/file-20210908-7120-1hsxjfw.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=512&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/419941/original/file-20210908-7120-1hsxjfw.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=512&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/419941/original/file-20210908-7120-1hsxjfw.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=643&fit=crop&dpr=1 754w, https://images.theconversation.com/files/419941/original/file-20210908-7120-1hsxjfw.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=643&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/419941/original/file-20210908-7120-1hsxjfw.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=643&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Male pot-bellied seahorse filling his pouch with water in a mating display.</span>
<span class="attribution"><span class="source">by Kymberlie R. McGuire</span></span>
</figcaption>
</figure>
<p>Embryonic development requires oxygen, and the oxygen demand increases as the embryo grows. So too does the need to get rid of the resulting carbon dioxide efficiently. This presents a problem for the pregnant male seahorse.</p>
<h2>Enter the placenta</h2>
<p>In egg-laying animals — such as birds, <a href="https://www.theguardian.com/science/2016/jun/08/australias-egg-laying-mammals-provide-clues-to-our-earliest-ancestor">monotremes</a>, certain reptiles and fishes — the growing embryo accesses oxygen and gets rid of carbon dioxide through pores in the egg shell.</p>
<p>For animals that give birth to live young, a different solution is required. Pregnant humans develop a placenta, a complex organ connecting the mother to her developing baby, which allows an efficient exchange of oxygen and carbon dioxide (it also gets nutrients to the baby, and removes waste, via the bloodstream).</p>
<p>Placentae are filled with many small blood vessels and often there is a thinning of the tissue layers that separate the parent’s and baby’s blood circulations. This improves the efficiency of oxygen and nutrient delivery to the fetus. </p>
<p>Surprisingly, the placenta is not unique to mammals. </p>
<p>Some sharks, like the Australian sharpnose shark (<em>Rhizoprionodon taylori</em>) <a href="https://pubmed.ncbi.nlm.nih.gov/33780667/">develop a placenta</a> with an umbilical cord joining the mother to her babies during pregnancy. Many <a href="https://pubmed.ncbi.nlm.nih.gov/16333627/">live-bearing lizards form a placenta</a> (including very complex <a href="https://www.discovermagazine.com/planet-earth/superfreak-of-evolution-the-lizard-with-a-humanlike-placenta">ones</a>) to provide respiratory gases and some nutrients to their developing embryos.</p>
<p>Our previous <a href="https://pubmed.ncbi.nlm.nih.gov/26330546/">research</a> identified genes that allow the seahorse father to provide for the developing embryos while inside his pouch.</p>
<p>Our new <a href="https://www.sciencedirect.com/science/article/abs/pii/S0143400421005816">study</a> shows that during pregnancy the pouch undergoes many changes similar to those seen in mammalian pregnancy. We focused on examining the brood pouch of male seahorses during pregnancy to determine exactly how they provide oxygen to their developing embryos. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/420405/original/file-20210910-19-rj928r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A Pot-belly seahorse (Hippocampus abdominalis) floats in water" src="https://images.theconversation.com/files/420405/original/file-20210910-19-rj928r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/420405/original/file-20210910-19-rj928r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/420405/original/file-20210910-19-rj928r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/420405/original/file-20210910-19-rj928r.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/420405/original/file-20210910-19-rj928r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/420405/original/file-20210910-19-rj928r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/420405/original/file-20210910-19-rj928r.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">By viewing the seahorse pouch under the microscope at various stages of pregnancy, we found that small blood vessels grow within the pouch.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>What we found</h2>
<p>By viewing the seahorse pouch under the microscope at various stages of pregnancy, we found that small blood vessels grow within the pouch, particularly towards the end of pregnancy. This is when the baby seahorses (called fry) require the most oxygen.</p>
<p>The distance between the father’s blood supply and the embryos also decreases dramatically as the pregnancy goes on. These changes improve the efficiency of transport between the father and the embryos. </p>
<p>Interestingly, many of the changes that occur in the seahorse pouch during pregnancy are similar to those that occur in the uterus during mammalian pregnancy. </p>
<p>We have only scratched the surface of understanding the function of the seahorse placenta during pregnancy.</p>
<p>There is still much to learn about how these fathers protect and nourish their babies during pregnancy — but our work shows the morphological changes to seahorse brood pouches have a lot in common with the development of mammalian placentae.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-secret-sex-life-and-pregnancy-of-a-seahorse-dad-46599">The secret sex life and pregnancy of a seahorse dad</a>
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</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/167534/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Camilla Whittington receives funding from the Australian Research Council and The University of Sydney.</span></em></p><p class="fine-print"><em><span>Jessica Suzanne Dudley does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>We examined male seahorse pouches under the microscope at different stages of pregnancy, and found they develop complex placental structures over time — in similar ways to human pregnancy.Jessica Suzanne Dudley, Postdoctoral Fellow, Macquarie UniversityCamilla Whittington, Senior lecturer, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1626622021-06-22T19:09:17Z2021-06-22T19:09:17ZHow a virtual placenta could help with early detection of at-risk babies<figure><img src="https://images.theconversation.com/files/407387/original/file-20210621-35190-a531nd.jpg?ixlib=rb-1.1.0&rect=12%2C172%2C4236%2C2650&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock/ESB Professional</span></span></figcaption></figure><p>None of us would be here without our placenta, the remarkable fetal organ that nourished and sustained us before birth. But despite its importance, the placenta is among the least studied organs and we don’t fully understand how it grows and functions. </p>
<p>This is problematic, because in one in ten pregnancies, the placenta functions poorly, leading to <a href="https://pubmed.ncbi.nlm.nih.gov/16580277/">pregnancy disorders</a> such as fetal growth restriction (<a href="https://www.tommys.org/pregnancy-information/pregnancy-complications/fetal-growth-restriction-intrauterine-growth-restriction">FGR</a>), when a baby’s growth slows dramatically or stops. Across <a href="https://www.aihw.gov.au/reports/mothers-babies/perinatal-deaths-in-australia-2013-2014/contents/table-of-contents">Australia</a> and <a href="https://www.hqsc.govt.nz/assets/PMMRC/Publications/14thPMMRCreport/Gestational_age_and_birthweight.pdf">New Zealand</a>, this affects more than 30,000 pregnancies each year, and growth-restricted babies are four times more likely to be stillborn. </p>
<p>Modern ultrasound imaging tools and new technologies such as fetal DNA testing in maternal blood cannot yet predict which pregnancies are at risk of fetal growth restriction until after the baby’s growth slows down. </p>
<p>To help improve early detection and prediction of at-risk pregnancies, we have developed a virtual placenta – a computer-based representation of the organ – by piecing together a wide range of clinical and laboratory data from pregnancies that go well and those that don’t. </p>
<p>The placenta has several functions. It delivers nutrients and oxygen from the mother’s blood to the baby, removes wastes from the baby back to mum, and produces important hormones that adapt mum’s body to pregnancy. Māori have always understood its value, referring to the placenta as the whenua, which nourishes the baby as the whenua (land) nourishes the people. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-does-a-baby-breathe-while-inside-its-mom-130349">How does a baby 'breathe' while inside its mom?</a>
</strong>
</em>
</p>
<hr>
<p>We know there are some important factors, including <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7093827/">smoking</a>, that can affect a baby’s growth. But pregnancy disorders can occur in healthy women with no risk factors, and in a culture where mothers are often quick to blame themselves, it’s important for women to know that growth restriction hardly ever occurs because of something they did or did not do. </p>
<p>The most common way to estimate fetal growth is by a tape measure on mum’s stomach, but the technique is only 10% sensitive, and even less so in patients who carry more body fat. More than half of the babies struggling to grow well are not detected before delivery. </p>
<h2>Virtual organs to detect health issues</h2>
<p>We need to do better at detecting fetal growth issues. The earlier doctors know these babies are at risk, the better. While treatment options are currently limited, doctors can monitor the pregnancy more closely and make informed decisions about when to deliver. </p>
<p>This is not straightforward, as both the mother’s and baby’s physiology can change quickly in pregnancy, and we can’t ask pregnant mothers to have more tests, or ultrasounds, or to undergo procedures that might put the pregnancy at risk (like using radiation in a CT scan). </p>
<p>The virtual placenta allows us to look more closely at pregnancy without adding to the burden of tests an expectant mother needs to undergo, and without costing the healthcare system an excessive amount. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/research-now-backs-routinely-offering-pregnant-women-the-mrna-covid-19-vaccine-162179">Research now backs routinely offering pregnant women the mRNA COVID-19 vaccine</a>
</strong>
</em>
</p>
<hr>
<p>Virtual organs, or indeed virtual humans, are <a href="http://physiomeproject.org">not a new concept</a>. For several decades scientists have been combining anatomical knowledge with the principles of physics to predict how changes in anatomy affect organ function. An example includes how changes in blood vessels affect how hard a heart has to pump to circulate blood around the body. </p>
<p>Simple virtual pregnancy models have guided <a href="https://www.sciencedirect.com/science/article/pii/0301562989900963">interpretation of ultrasound</a> since the start of routine use in pregnancy in the 1980s.</p>
<p>Virtual clinical trials are also emerging where it is possible to experiment on a computer-based organ to predict outcomes before new treatments are trialled on real people. This reduces animal testing and the cost of clinical trials. </p>
<h2>Earlier detection of problems</h2>
<figure class="align-right ">
<img alt="An illustration of the placenta" src="https://images.theconversation.com/files/407381/original/file-20210621-35149-1acw5tp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/407381/original/file-20210621-35149-1acw5tp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=638&fit=crop&dpr=1 600w, https://images.theconversation.com/files/407381/original/file-20210621-35149-1acw5tp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=638&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/407381/original/file-20210621-35149-1acw5tp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=638&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/407381/original/file-20210621-35149-1acw5tp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=802&fit=crop&dpr=1 754w, https://images.theconversation.com/files/407381/original/file-20210621-35149-1acw5tp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=802&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/407381/original/file-20210621-35149-1acw5tp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=802&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">An illustration of a virtual placenta, with large arteries branching like a tree to deliver fetal blood to the site of exchange.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The placenta is like a dense forest of trees. The baby’s own blood vessels are inside the branches of these trees, while blood from mum’s uterus flows around the outside. How blood flows in both these circulations is critical for good exchange. </p>
<p>Only recently has technology allowed virtual placentas to include the <a href="https://wires.onlinelibrary.wiley.com/doi/full/10.1002/wsbm.1502">detail of this blood flow and exchange</a>, which can’t be measured directly. This is allowing scientists to make strides towards understanding how features of placentas that restrict a baby’s growth show up in imaging like ultrasound or MRI. </p>
<p>Finding cost-effective ways to predict and detect fetal growth restriction will go a long way to helping our smallest babies. Predicting which pregnancies are at risk in early pregnancy is especially important, as this is when the placenta is growing rapidly, and therapies delivered in early pregnancy are more likely to bolster placental function. For example, simple and safe therapies such as aspirin are effective at reducing fetal growth restriction, but only if started before 16 weeks of pregnancy.</p>
<p>As we cannot predict FGR in early pregnancy, much of what we know about restricted growth in utero comes from studies in late pregnancy, and assessment of placentas after delivery. Applying our anatomical understanding of earlier stages of placental development allows us to virtually “turn back the clock” and consider early contributors to poor placental function, and how we can measure these by ultrasound. </p>
<p>We hope to use this knowledge to develop new ways to predict at-risk pregnancies, so we can help prevent growth issues, and give all babies a better start to life.</p><img src="https://counter.theconversation.com/content/162662/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alys Clark receives funding from the Health Research Council of New Zealand and the Royal Society Te Aparangi and Ministry of Business, Innovation and Employment (New Zealand). </span></em></p><p class="fine-print"><em><span>Jo James receives funding from the Royal Society Te Apārangi, the Nurture Foundation for Reproductive Research and the RANZCOG Mercia Barnes Trust. </span></em></p>The placenta is one of the least studied organs, but it is the cause of problems in one in ten pregnancies. A virtual placenta is helping researchers to pick up at-risk pregnancies sooner.Alys Clark, Associate Professor in Bioengineering, University of Auckland, Waipapa Taumata RauJo James, Associate Professor in Obstetrics and Gynaecology, University of Auckland, Waipapa Taumata RauLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1303492020-05-05T12:46:15Z2020-05-05T12:46:15ZHow does a baby ‘breathe’ while inside its mom?<figure><img src="https://images.theconversation.com/files/332496/original/file-20200504-83721-wei11m.jpg?ixlib=rb-1.1.0&rect=1134%2C396%2C6214%2C4506&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Her deep breath has to get to the baby.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/pregnant-woman-sitting-outside-royalty-free-image/1132797740">electravk/Moment via Getty Images</a></span></figcaption></figure><p>“Mothering” is synonymous with “nurturing,” probably because moms start providing for their kids even before they’re born. </p>
<p>A fetus relies on its mother to provide all the essentials. The placenta is key here; this organ develops in the uterus and is like a gateway that lets mom pass baby everything it needs to support its development.</p>
<p>After the mother eats, her body breaks the food down into glucose, amino acids, fatty acids and cholesterol that travel through channels or <a href="https://doi.org/10.3390/ijms150916153">transporters in the placenta to the fetus</a>. They provide the energy and the building blocks that the growing fetus uses as it develops organs, tissues and bones.</p>
<p>Vital electrolytes like <a href="https://doi.org/10.1093/bjaceaccp/mku013">sodium, chloride, calcium and iron</a> pass through their own specific channels in the placenta or just diffuse from the mother’s side to the fetus’s.</p>
<p>Fetuses require oxygen for growth, too. Since their lungs are not exposed to air, they can’t breathe on their own. Instead they rely on their mothers to provide the required oxygen through a remarkable biochemical process. </p>
<p><a href="https://scholar.google.com/citations?user=DL4ZkpIAAAAJ&hl=en">I’m a biochemist</a>, and it’s this process that made me fall in love with the discipline when I was a student. It’s my favorite topic to present to my students today and helps explain why pregnant women can get so easily winded. </p>
<h2>Oxygen running through your veins</h2>
<p>Some ingenious biochemistry is at the root of how oxygen travels throughout the human body.</p>
<p>A protein called hemoglobin is responsible for picking up oxygen in your lungs and carrying it via your bloodstream to all of your tissues. <a href="https://www.acs.org/content/acs/en/education/resources/highschool/chemmatters/past-issues/archive-2009-2010/chemmatters-february-2010-issue.html">Hemoglobin contains iron</a>, and it’s responsible for <a href="https://theconversation.com/blood-in-your-veins-is-not-blue-heres-why-its-always-red-97064">blood’s red color</a>. It’s made up of four subunits, two each of two different types. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/326586/original/file-20200408-118674-h9npux.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/326586/original/file-20200408-118674-h9npux.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/326586/original/file-20200408-118674-h9npux.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=307&fit=crop&dpr=1 600w, https://images.theconversation.com/files/326586/original/file-20200408-118674-h9npux.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=307&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/326586/original/file-20200408-118674-h9npux.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=307&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/326586/original/file-20200408-118674-h9npux.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=386&fit=crop&dpr=1 754w, https://images.theconversation.com/files/326586/original/file-20200408-118674-h9npux.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=386&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/326586/original/file-20200408-118674-h9npux.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=386&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Hemoglobin’s four subunits – two blue and two green in the illustration – can bind to one oxygen molecule each.</span>
<span class="attribution"><span class="source">Image generated from PBD ID 1C7B by Julie Pollock</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Each subunit contains one iron atom bound to a special compound called a heme that can interact with one oxygen molecule. It’s an all-or-nothing situation; for hemoglobins in the same vicinity, they’re either all holding onto oxygen or have all released their oxygen. It depends on the concentration of oxygen in the environment the hemoglobin finds itself in. </p>
<p>When you take a good breath, the concentration of oxygen is high in your lungs. Hemoglobin in the area automatically picks up oxygen. Then it travels via your blood to tissues with lower oxygen concentrations, where it gives up the oxygen.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/332492/original/file-20200504-83740-1j3brd.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/332492/original/file-20200504-83740-1j3brd.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/332492/original/file-20200504-83740-1j3brd.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=270&fit=crop&dpr=1 600w, https://images.theconversation.com/files/332492/original/file-20200504-83740-1j3brd.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=270&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/332492/original/file-20200504-83740-1j3brd.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=270&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/332492/original/file-20200504-83740-1j3brd.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=339&fit=crop&dpr=1 754w, https://images.theconversation.com/files/332492/original/file-20200504-83740-1j3brd.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=339&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/332492/original/file-20200504-83740-1j3brd.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=339&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">BPG binds to hemoglobin to facilitate the release of oxygen.</span>
<span class="attribution"><a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>A molecule called 2,3-bisphosphoglycerate, or BPG, facilitates oxygen’s release. It binds to the center cavity between the four subunits of hemoglobin to help the oxygen molecules pop free. </p>
<h2>Getting oxygen to the fetus</h2>
<p>Fetuses are not exposed to air, and their <a href="https://doi.org/10.1146/annurev.ph.46.030184.003153">lungs don’t fully develop until after they’re born</a>, so oxygen is another on the long list of things they must get through the placenta from their mothers.</p>
<p>Hemoglobin proteins are too big to cross the placenta. The maternal hemoglobins must give up their oxygen molecules on their side so the oxygen can cross over and be picked up by the fetal hemoglobins on the other side. The predicament is that since this is all happening in such close quarters, the hemoglobins should either all be holding on to oxygen or all be releasing it.</p>
<p>In order to circumvent this problem, <a href="https://www.wiley.com/en-us/Essential+Biochemistry%2C+3rd+Edition-p-9781118441688">fetal hemoglobin differs in structure</a> from maternal hemoglobin. With just a few changes to the amino acids in its protein sequence, fetal hemoglobin does not bind well to BPG, the molecule that helps oxygen get loose from adult hemoglobin. Fetal hemoglobin also has a stronger affinity for oxygen than the adult version does.</p>
<p>So at the placental interface, where there’s a lot of BPG, the maternal hemoglobin lets go of the oxygen and the fetal hemoglobin grabs ahold of it tightly. This process allows for effective and efficient transfer of oxygen from the mother to the fetus.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/332493/original/file-20200504-83740-101e5wu.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/332493/original/file-20200504-83740-101e5wu.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/332493/original/file-20200504-83740-101e5wu.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=359&fit=crop&dpr=1 600w, https://images.theconversation.com/files/332493/original/file-20200504-83740-101e5wu.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=359&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/332493/original/file-20200504-83740-101e5wu.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=359&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/332493/original/file-20200504-83740-101e5wu.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=451&fit=crop&dpr=1 754w, https://images.theconversation.com/files/332493/original/file-20200504-83740-101e5wu.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=451&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/332493/original/file-20200504-83740-101e5wu.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=451&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Effective transfer of oxygen from maternal hemoglobin (blue and green) to fetal hemoglobin (purple and green) is facilitated by BPG at the placenta.</span>
<span class="attribution"><a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Shortly before babies are born, they start making some adult hemoglobin so that when they are breathing on their own, they can perform appropriate oxygen transfer throughout their little bodies. <a href="https://doi.org/10.1016/j.ebiom.2016.11.032">Usually by the time a baby reaches six months of age</a>, the levels of fetal hemoglobin are very low, replaced almost completely by adult hemoglobin.</p>
<p>Academically, I knew about this remarkable biochemical process. But it wasn’t until I was pregnant with my son that I really understood it. My miles in spinning class decreased, I lagged behind my husband and dog on our daily walks, and I ran out of breath climbing the three flights of stairs to my office. My son’s hemoglobin was stealing my oxygen, so I had to breathe in more to complete routine tasks.</p>
<p>Once my baby was on the outside, breathing on his own with his mature hemoglobin functioning appropriately, I was more amazed than ever at the perfection of the science.</p>
<p>[<em>Insight, in your inbox each day.</em> <a href="https://theconversation.com/us/newsletters?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=insight">You can get it with The Conversation’s email newsletter</a>.]</p><img src="https://counter.theconversation.com/content/130349/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Julie Pollock has received research funding from the Virginia Academy of Sciences and the Jeffress Memorial Trust. </span></em></p>A fetus needs oxygen long before its lungs work and it’s exposed to the air. Some ingenious biochemistry explains how the mother’s blood delivers it.Julie Pollock, Associate Professor of Chemistry, University of RichmondLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1171862019-05-17T00:57:49Z2019-05-17T00:57:49ZThis is what happens to a baby’s body during birth<figure><img src="https://images.theconversation.com/files/274849/original/file-20190516-69186-1kh744n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Delivering a human baby – which has a large, highly developed brain – is risky for mother and baby. </span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/jaredandmelanie/3910068599/in/photolist-6Xw8aR-4M1Qgi-32KH7E-fes1T-bi4q7M-32FemR-5pUF8-4Njcrh-4nKQW7-3fenap-7pvWsb-6Axr4B-9471k4-9sMEEB-4w6oaW-sEnKmc-4WXHG4-22eE5cG-YueHnd-S59ayg-J2gaD-pBaPGx-bi4rbz-bi4kXT-36bjYJ-EnJtT9-S3DNGi-23Cxgwt-o8khJi-aMHoBZ-6e5VRE-8tfkDw-dMWbJQ-P6mcpe-avETXg-RVJb3Z-5pxaZK-23NtttT-rzKddE-RHagrR-hpbpu3-5SEAjJ-asN4wg-29bzzpx-7k1Xdc-hcAsgj-3femG8-3fekYe-3fiJMd-awZ2LT">jaredandmelanie/flickr </a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Pregnancy, labour and delivery are incredibly physically demanding for women. But birth is no walk in the park for the baby either.</p>
<p>A <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0215721">new paper</a> reveals just how much a baby’s head is pushed and distorted by vaginal delivery. </p>
<p>By recording MRI scans before and during labour, the researchers show the degree to which a baby’s skull bones ride over each other, allowing the whole skull to morph. The baby’s head becomes a sugarloaf shape – an elongated cone, with a rounded tip at one end – to get through the pelvis. The brain itself changes form as this happens too.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/274850/original/file-20190516-69186-16bgyk9.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/274850/original/file-20190516-69186-16bgyk9.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/274850/original/file-20190516-69186-16bgyk9.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=424&fit=crop&dpr=1 600w, https://images.theconversation.com/files/274850/original/file-20190516-69186-16bgyk9.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=424&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/274850/original/file-20190516-69186-16bgyk9.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=424&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/274850/original/file-20190516-69186-16bgyk9.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=533&fit=crop&dpr=1 754w, https://images.theconversation.com/files/274850/original/file-20190516-69186-16bgyk9.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=533&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/274850/original/file-20190516-69186-16bgyk9.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=533&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Three-dimensional fetal brain MRI reconstruction shows the shape of a baby’s brain before labor (purple in A, C, E) and during the second stage of labor (orange in B, D, F).</span>
<span class="attribution"><a class="source" href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0215721">Olivier Amie and co-authors</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Head compression is just one of the many incredible physical changes that takes place in infants during birth. Babies undergo a massive transition during labour and delivery as they move from the supported environment of the uterus to independent existence. </p>
<p>Many body systems change to do this. Some have already been in transition. For example, urine output from the fetus contributes to the amniotic fluid (the liquid that surrounds the baby) in the later part of pregnancy. Other organs require a sudden change in the first few moments after delivery, such as expansion of the lungs. </p>
<p>These biological events are vital to maximise chances of survival in the first few minutes “outside”. But surprisingly, we are still learning many of the details.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/health-check-how-long-should-i-wait-between-pregnancies-106079">Health Check: how long should I wait between pregnancies?</a>
</strong>
</em>
</p>
<hr>
<h2>Sudden increase in oxygen</h2>
<p>Before the baby is born, blood goes through the placenta to get rid of waste and to pick up oxygen and nutrients that come from the mother. The developing baby manages on relatively low oxygen levels while in the uterus. </p>
<p>After birth the child is exposed to suddenly higher (potentially dangerous) oxygen levels. This shift requires different ways to protect the newborn – so the baby has systems ramped up to cope with this sudden flood of oxygen. Mild jaundice, a temporary yellowing of the skin resulting from a delay in liver enzymes kicking in, may be <a href="https://doi.org/10.3389/fphar.2012.00030">one such protective mechanism</a> seen in many infants. </p>
<p>Physical changes plus shifts in biology and chemistry of the body’s systems are required to cope with the outside world. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/275025/original/file-20190516-69209-bheyt9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/275025/original/file-20190516-69209-bheyt9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/275025/original/file-20190516-69209-bheyt9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/275025/original/file-20190516-69209-bheyt9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/275025/original/file-20190516-69209-bheyt9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/275025/original/file-20190516-69209-bheyt9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/275025/original/file-20190516-69209-bheyt9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/275025/original/file-20190516-69209-bheyt9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The baby on the right has jaundice.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/rubyturquoise/12546968393/in/photolist-k7Juzg-6DYnQd-9AGEz4-aixZ2f-9jjhqS-6TLz73-9yaGj3-6mVPPp-qsJc9-syq4k-nKTKK-fCP34-b2zMvD-aMsXR-bnDLK-kke7d-8zSZLq-fjrHmd-7zPb3g-84KbEt-3jVLkG-htPDAJ-3X3LKL-6PvV3A-bnDzX-rRUxD-zh8sn-iU5jq5-gxG7r6-4m3p1A-KVnfc-bnDH3-wYS1J-4WxYLR-dMvHWF-mBHbJ-9eLdt-4naNPu-8VWXyH-rjQEA-4bwAM6-4VSW7e-4yfQDy-fjrjwL-5bQBGW-5w4UT6-62MASZ-q54YeB-6cpWU1-srdD8">rubyturquoise/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Goodbye placenta</h2>
<p>Before birth, most of the baby’s blood circulation passes through the placenta, but bypasses the lungs. </p>
<p>After delivery, the placental flow stops. Instead of going from the baby’s heart to the placenta, the blood from the heart needs to redirect through the newly expanded lungs. </p>
<p><a href="https://doi.org/10.1016/j.resuscitation.2018.07.008">New research</a> helps us understand the relationship between baby’s first breaths and the expansion of lung blood flow. </p>
<p>Understanding these processes in the first few minutes guides us in knowing when exactly to clamp the umbilical cord, and to time any breathing help needed for sick or premature newborns. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/274895/original/file-20190516-69174-6mpymq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/274895/original/file-20190516-69174-6mpymq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/274895/original/file-20190516-69174-6mpymq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/274895/original/file-20190516-69174-6mpymq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/274895/original/file-20190516-69174-6mpymq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/274895/original/file-20190516-69174-6mpymq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/274895/original/file-20190516-69174-6mpymq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/274895/original/file-20190516-69174-6mpymq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Once born, the baby must take over many of the biological processes the placenta performed during pregnancy.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/cutting-umbilical-cord-between-newborn-baby-1102051622?src=cY2dbRtfVFR88sCcZceBlw-1-8">from www.shutterstock.com</a></span>
</figcaption>
</figure>
<h2>It doesn’t always go to plan</h2>
<p>The many changes a baby needs to be ready for delivery do not always have a chance to take place. </p>
<p>For example, if a baby is born prematurely then some or all of these adaptations may not have occurred. </p>
<p>Premature babies may have trouble opening up their lungs, or they may not close off the <a href="https://www.heart.org/en/health-topics/congenital-heart-defects/about-congenital-heart-defects/patent-ductus-arteriosus-pda">relevant bits of “plumbing”</a> to redirect blood flow to the lungs. Or they may have difficulty exchanging oxygen and other gases in the lungs. </p>
<p>Other body systems such as skin, guts and the body’s chemistry systems may also be relatively unprepared. </p>
<p>Despite this, all but the most premature of babies benefit from the boost of labour if possible. The changes associated with the onset of labour, particularly inflammation, trigger the biological signals that tell a baby to get ready for being born.</p>
<h2>Caesarian delivery</h2>
<p>Surprisingly, even a small deviation from normal, full-term (around 40 weeks) timing of labour may have effects. </p>
<p>Babies born by caesarean section without labour do not transition to the outside world as smoothly as those where labour has commenced. They have a <a href="https://www.ranzcog.edu.au/RANZCOG_SITE/media/RANZCOG-MEDIA/Women%27s%20Health/Statement%20and%20guidelines/Clinical-Obstetrics/Timing-of-elective-caesarean-section-(C-Obs-23)-March18.pdf?ext=.pdf">higher rate of admission</a> to neonatal units for respiratory problems, even after adjusting for other risk factors. Every week earlier than delivery at 40 weeks roughly <a href="https://www.ranzcog.edu.au/RANZCOG_SITE/media/RANZCOG-MEDIA/Women%27s%20Health/Statement%20and%20guidelines/Clinical-Obstetrics/Timing-of-elective-caesarean-section-(C-Obs-23)-March18.pdf?ext=.pdf">doubles the risk of neonatal unit admission</a> for babies. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/274900/original/file-20190516-69209-11faw5a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/274900/original/file-20190516-69209-11faw5a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/274900/original/file-20190516-69209-11faw5a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/274900/original/file-20190516-69209-11faw5a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/274900/original/file-20190516-69209-11faw5a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/274900/original/file-20190516-69209-11faw5a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/274900/original/file-20190516-69209-11faw5a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/274900/original/file-20190516-69209-11faw5a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Birth by caesarian section is an entirely different biological experience for the baby – and may have some health consequences.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/baby-being-born-via-caesarean-section-1175133850?src=qhE01eBBXWjqYsPq_e8s4g-1-28">from www.shutterstock.com</a></span>
</figcaption>
</figure>
<p>Current recommendations for birth timing are to balance the risks of delivery with these immaturity risks, and not deliver too early unless it is medically required. </p>
<p>Some of these effects can be altered by steroids. Steroids are made naturally by our bodies, including in babies. Also referred to as “the body’s stress hormones”, these are particularly important in making sure lung maturity happens at birth. </p>
<p>Sometimes steroids given to the mother can trick the baby into “preparing an escape plan” and getting lungs ready for delivery before term. </p>
<p>Independent of mild prematurity, researchers are <a href="https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(18)31930-5/fulltext">looking closely</a> to determine if there are any long term health and developmental effects of being born by caesarean section, without the process of labour and delivery. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/explainer-what-is-pre-eclampsia-and-how-does-it-affect-mums-and-babies-97781">Explainer: what is pre-eclampsia, and how does it affect mums and babies?</a>
</strong>
</em>
</p>
<hr>
<h2>Squashed head</h2>
<p>But why do we have such a high-risk delivery system, one where the baby has to actually deform its skull to be born? </p>
<p>Humans are defined by our brains. In our species, the process of evolution has been a balancing act, where brain size and maturity have been weighed up (in terms of survival) against the risk of obstruction in labour. </p>
<p>Human babies are relatively immature compared with some of our close primate relatives, but we cannot safely achieve more brain growth before delivery. For us, this extra growth has to occur over the first year or so after birth. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/274901/original/file-20190516-69213-1d62p6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/274901/original/file-20190516-69213-1d62p6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/274901/original/file-20190516-69213-1d62p6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/274901/original/file-20190516-69213-1d62p6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/274901/original/file-20190516-69213-1d62p6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/274901/original/file-20190516-69213-1d62p6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/274901/original/file-20190516-69213-1d62p6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/274901/original/file-20190516-69213-1d62p6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Gorillas and other primates give birth to babies that are much more developmentally advanced than human babies.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/female-gorilla-newborn-baby-7631824?src=XHM-b4MM648fYny7IW58Uw-1-8">from www.shutterstock.com</a></span>
</figcaption>
</figure>
<p>In addition, because we walk upright, this has created a tilt in our pelvis which narrows the birth canal (the gap in the bones of the pelvis through which the baby has to pass). </p>
<p>Birth is still risky. Globally, obstructed labour is still a significant cause of both <a href="https://www.who.int/healthinfo/statistics/bod_obstructedlabour.pdf">mother and baby deaths</a>, and a major cause of long-term incontinence disabilities in <a href="https://www.who.int/healthinfo/statistics/bod_obstructedlabour.pdf">mothers that do survive</a>. This tightrope we humans walk between head size and the potential of terrible mother and baby outcomes is essentially the driver for the existence of modern obstetrics. </p>
<p>We hope that more research aimed at understanding the balance of those risks, plus looking at how babies transition from uterus to the outside world, will help us better manage safe birthing. This will improve immediate and long-term health for mothers and their babies.</p><img src="https://counter.theconversation.com/content/117186/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ian Wright receives funding from the Australian National Health and Medical Research Council. </span></em></p>Babies undertake a massive transition during labour and delivery as they move from the supported environment of the uterus to independent existence.Ian Wright, Professor of Paediatrics and Child Health Research, University of WollongongLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1134602019-04-02T23:14:51Z2019-04-02T23:14:51ZThe first known case of eggs plus live birth from one pregnancy in a tiny lizard<p>For most animals, reproduction is straightforward: some species lay eggs, while others give birth to live babies. </p>
<p>But our <a href="https://royalsocietypublishing.org/doi/10.1098/rsbl.2018.0827">recent research</a> uncovered a fascinating mix between the two modes of reproduction. In an Australian skink, we observed the first example of both egg-laying and live-bearing within a single litter for any backboned animal. </p>
<p>This suggests some lizards can “hedge their bets” reproductively, taking a punt on both eggs and live-born babies to improve overall survival chances for offspring. </p>
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<strong>
Read more:
<a href="https://theconversation.com/ancient-fossil-fills-a-75-million-year-gap-and-rewrites-lizard-and-snake-history-97455">Ancient fossil fills a 75 million-year gap and rewrites lizard and snake history</a>
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<h2>Making reproductive leaps</h2>
<p>Most vertebrate species (animals with a backbone) fall neatly into one of two distinctly different reproductive categories. </p>
<p>Oviparous species are egg-layers. These eggs may undergo external fertilisation – such as in spawning fish – or are fertilised and shelled internally, like those of reptiles and birds. Oviparous embryos rely on egg yolk as a source of nutrition to continue development until hatching. </p>
<p>In contrast, viviparous species are live bearers that carry their young to term. Some live-bearing species, including humans, support embryonic development internally via a placenta. <a href="https://www.ncbi.nlm.nih.gov/pubmed/24652663">Egg-laying is ancestral</a>, meaning that modern live-bearers have descended from egg-laying ancestors.</p>
<p>Physiologically, the evolution of live birth from egg-laying is no mean feat. This transition requires a <a href="https://www.ncbi.nlm.nih.gov/pubmed/11923079">whole suite of changes</a>, sometimes including the <a href="https://theconversation.com/using-the-placenta-to-understand-how-complex-organs-evolve-70107">evolution of a placenta</a> – an entirely new specialist organ – as well as loss of the hard outer eggshell, and keeping the embryo inside the body for a longer time. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/266982/original/file-20190402-177181-r7xy8r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/266982/original/file-20190402-177181-r7xy8r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/266982/original/file-20190402-177181-r7xy8r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/266982/original/file-20190402-177181-r7xy8r.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/266982/original/file-20190402-177181-r7xy8r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/266982/original/file-20190402-177181-r7xy8r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/266982/original/file-20190402-177181-r7xy8r.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The placenta is a highly complex organ. One of its jobs is to transfer nutrition to the developing baby.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/cutting-umbilical-cord-between-newborn-baby-1102051619">from www.shutterstock.com</a></span>
</figcaption>
</figure>
<p>Despite these complex steps, reptiles, particularly snakes and lizards, appear to be unusually predisposed to making the leap to live birth. This capacity has <a href="https://www.ncbi.nlm.nih.gov/pubmed/24652663">evolved in at least 115 groups of reptiles independently</a>. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/a-hidden-toll-australias-cats-kill-almost-650-million-reptiles-a-year-98854">A hidden toll: Australia's cats kill almost 650 million reptiles a year</a>
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<hr>
<h2>Having it both ways</h2>
<p>It’s easy to see why reptiles, as a group, are <a href="https://www.ncbi.nlm.nih.gov/pubmed/11923079">fascinating models</a> for studying how live birth evolves from egg-laying. </p>
<p>Of particular interest are two Australian skinks that have both live-bearing and egg-laying individuals (known as being <a href="https://theconversation.com/lizards-help-us-find-out-which-came-first-the-baby-or-the-egg-29954">bimodally reproductive</a>). These lizards are incredibly valuable to evolutionary biologists as they offer a snapshot into evolutionary processes in action. </p>
<p>The three-toed skink <em>Saiphos equalis</em> is one such species. Reproduction in <em>S. equalis</em> <a href="https://academic.oup.com/biolinnean/article/74/2/131/2639614">varies geographically</a>: populations around Sydney lay eggs, while those further north give birth to live young. </p>
<p>Whether individuals are live-bearing or egg-laying seems to be genetically determined: when researchers swap their environmental conditions (by moving them from one site to another), the <a href="http://www.publish.csiro.au/zo/ZO97023">females retain their original reproductive strategy</a>.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/lizards-help-us-find-out-which-came-first-the-baby-or-the-egg-29954">Lizards help us find out which came first: the baby or the egg?</a>
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<hr>
<h2>Mothers know best</h2>
<p><a href="https://royalsocietypublishing.org/doi/10.1098/rsbl.2018.0827">Our latest research</a> shows this lizard is intriguing in another completely unexpected way. </p>
<p>We observed a live-bearing female that laid three eggs, and then gave birth to a living baby from the same litter weeks later. We incubated two of the eggs, one of which hatched to produce a healthy baby. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/264496/original/file-20190318-28512-b7g67t.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/264496/original/file-20190318-28512-b7g67t.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/264496/original/file-20190318-28512-b7g67t.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=283&fit=crop&dpr=1 600w, https://images.theconversation.com/files/264496/original/file-20190318-28512-b7g67t.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=283&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/264496/original/file-20190318-28512-b7g67t.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=283&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/264496/original/file-20190318-28512-b7g67t.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=355&fit=crop&dpr=1 754w, https://images.theconversation.com/files/264496/original/file-20190318-28512-b7g67t.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=355&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/264496/original/file-20190318-28512-b7g67t.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=355&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A live-bearing female <em>S. equalis</em> in our laboratory colony laid three eggs, one of which hatched to produce a healthy baby.</span>
<span class="attribution"><span class="source">Camilla Whittington</span></span>
</figcaption>
</figure>
<p>This finding is remarkable for two reasons. First, as far as we are aware, this is the first example of both egg-laying and live birth within a single litter for any vertebrate. </p>
<p>Second, in some cases, individuals may be capable of “switching” between reproductive modes. In other words, as laying eggs and giving birth each come with their own advantages and disadvantages, individuals may be able to “choose” which option best suits the current situation.</p>
<h2>Closer look at eggshells</h2>
<p>To better understand this reproductive phenomenon, we investigated the structure of the egg coverings of these unusual embryos in minute detail (using an advanced technology called scanning electron microscopy). </p>
<p>We found that in this litter, the egg-coverings were thinner than those of normal egg-laying skinks and had structural characteristics that overlapped with those of both egg-layers and live-bearers (which have thinner coverings that are greatly reduced). </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/264499/original/file-20190318-28475-9pey9.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/264499/original/file-20190318-28475-9pey9.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/264499/original/file-20190318-28475-9pey9.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=185&fit=crop&dpr=1 600w, https://images.theconversation.com/files/264499/original/file-20190318-28475-9pey9.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=185&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/264499/original/file-20190318-28475-9pey9.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=185&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/264499/original/file-20190318-28475-9pey9.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=233&fit=crop&dpr=1 754w, https://images.theconversation.com/files/264499/original/file-20190318-28475-9pey9.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=233&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/264499/original/file-20190318-28475-9pey9.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=233&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Egg coverings of <em>S. equalis</em> consist of an outer crust (C) and an inner shell membrane (SM). We compared the structure and thicknesses of these layers of both egg-laying (A) and live-bearing (B) <em>S. equalis</em> to identify similarities with our ‘unusual’ embryos (C).</span>
<span class="attribution"><span class="source">Melanie Laird</span></span>
</figcaption>
</figure>
<h2>How evolution works</h2>
<p>We still don’t know the trigger that caused this female to lay eggs and give birth to a live baby from the same pregnancy. </p>
<p>However, our findings suggest that species “in transition” between egg-laying and live bearing may hedge their bets reproductively before a true transition to live birth evolves. </p>
<p>Being able to switch between reproductive modes may be advantageous, particularly in changing or uncertain environments. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/266985/original/file-20190402-177199-sq0hc5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/266985/original/file-20190402-177199-sq0hc5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/266985/original/file-20190402-177199-sq0hc5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/266985/original/file-20190402-177199-sq0hc5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/266985/original/file-20190402-177199-sq0hc5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/266985/original/file-20190402-177199-sq0hc5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/266985/original/file-20190402-177199-sq0hc5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The three-toed skink lives in eastern Australia.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/dougbeckers/7464211152/in/photolist-cnA2VJ">Doug Beckers / flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>For example, extreme cold, drought or the presence of predators can be risky for vulnerable eggs exposed to the environment, meaning that mothers that can carry offspring to term may have the upper hand. </p>
<p>In contrast, lengthy pregnancies can be taxing on the mother, so depositing offspring earlier as an egg may be beneficial in some situations. </p>
<p>We suggest that other species in which live birth has evolved from egg-laying relatively recently may also use flexible reproductive tactics. </p>
<p>Further research into this small Australian lizard, which seems to occupy the grey area between live birth and egg-laying, will help us determine how and why species make major reproductive leaps.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/curious-kids-why-do-hens-still-lay-eggs-when-they-dont-have-a-mate-104077">Curious Kids: why do hens still lay eggs when they don't have a mate?</a>
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<img src="https://counter.theconversation.com/content/113460/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Melanie Laird receives funding from The University of Otago. </span></em></p><p class="fine-print"><em><span>Camilla Whittington receives funding from the Australian Research Council. </span></em></p>The evolution of live birth from egg-laying is no mean feat. Now new research reports on the first known example where both eggs and a live birth come from the same lizard pregnancy.Melanie Laird, Postdoctoral Fellow, University of OtagoCamilla Whittington, Senior lecturer, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1116252019-02-14T19:07:53Z2019-02-14T19:07:53ZYou need more than just testes to make a penis<figure><img src="https://images.theconversation.com/files/258965/original/file-20190214-1721-14ua0u2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Testosterone is primarily made in the testes, and creates many of the characteristics we see in adult men. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/jeans-man-on-dark-background-766127614">from www.shutterstock.com</a></span></figcaption></figure><p>In prenatal ultrasounds or at delivery, many new parents look between their baby’s legs: the presence of a penis is taken as a strong sign that it’s a boy.</p>
<p>For humans and other animals, development of a penis was thought to be driven by “male hormones” (androgens) produced entirely by the testes of the male fetus as it grows in the uterus. </p>
<p>However, a <a href="http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3000002">new paper</a> released today indicates this might not be the case. Instead, some of the masculinising hormones that drive penis development may come from other sources in the developing fetus. These include the liver, the adrenals (small glands found on the kidneys) and placenta. </p>
<p>For the first time, this work comprehensively looks at the possible sites of hormone production outside the testes and their role in regulating masculinisation – the process of gaining typical male characteristics. This helps us see how we develop as embryos, and might feed into a bigger picture of why disorders of penis development are increasing.</p>
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<p>
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Read more:
<a href="https://theconversation.com/our-relationship-with-dick-pics-its-complicated-103444">Our relationship with dick pics: it's complicated</a>
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</em>
</p>
<hr>
<h2>Testosterone is not enough</h2>
<p>The penis develops from an embryonic structure called the genital tubercle or GT. </p>
<p>The GT is present in both males and females, and develops into either a clitoris or penis, depending on its exposure to hormones secreted by the developing gonads (ovaries or testes). </p>
<p>In females, the developing ovaries do not produce early hormones and the GT becomes feminised, forming a clitoris. </p>
<p>In males, the developing testes produce testosterone. This circulates in the developing fetus and causes masculinisation of target tissues and induces penis development from the GT. </p>
<p>Testosterone itself is a relatively weak hormone. It is converted in the penis to another hormone called dihydrotestosterone (DHT), which has a much more potent masculinising effect. </p>
<p>It is the local conversion of testosterone to DHT within the tissue that is important for penis development and other changes. </p>
<p>There are several ways in which the fetus can make DHT. The most simple is via conversion from testicular testosterone (the so-called “canonical” pathway). However, DHT can also be produced via other steroid hormone pathways active in many tissues, which is explored further in this new paper. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-makes-you-a-man-or-a-woman-geneticist-jenny-graves-explains-102983">What makes you a man or a woman? Geneticist Jenny Graves explains</a>
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<hr>
<h2>Common birth defects</h2>
<p>Understanding the pathways that control penis development is important. Disorders affecting penis development are among the most common birth defects seen in humans, with hypospadias (a disorder affecting development of the urethra) currently affecting around <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2083775/">1 in every 115 live males born in Australia</a>, and rates are on the rise. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/258647/original/file-20190213-90504-lw517s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/258647/original/file-20190213-90504-lw517s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=424&fit=crop&dpr=1 600w, https://images.theconversation.com/files/258647/original/file-20190213-90504-lw517s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=424&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/258647/original/file-20190213-90504-lw517s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=424&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/258647/original/file-20190213-90504-lw517s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=533&fit=crop&dpr=1 754w, https://images.theconversation.com/files/258647/original/file-20190213-90504-lw517s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=533&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/258647/original/file-20190213-90504-lw517s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=533&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The urethra, the hole through which urine passes out of the body, is found in a range of different locations in the disorder known as hypospadias</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-vector/newborn-malformation-hypospadia-main-types-315283037?src=q7V1zs7wS25RVKHm_q7jsg-1-2">from www.shutterstock.com</a></span>
</figcaption>
</figure>
<p>In fact, the incidence of hypospadias has <a href="https://www.ncbi.nlm.nih.gov/pubmed/11392374">doubled over the past 40 years</a>. Such a rapid increase in incidence has been attributed to environmental factors, with endocrine disrupting chemicals (EDCs) being proposed as a major cause. EDCs are man-made chemicals used in many industries – for example, in the production of plastics, cosmetics, flame retardants and pesticides. They can interfere with hormone and metabolic systems in our bodies.</p>
<p>Of the <a href="https://endocrinedisruption.org/interactive-tools/tedx-list-of-potential-endocrine-disruptors/search-the-tedx-list">1,484 EDCs currently identified</a>, a large number are known to negatively affect male reproductive development. </p>
<p>Many <a href="https://www.publish.csiro.au/RD/RD18505">studies</a> have identified how EDCs negatively affect organs, such as the liver and adrenals, leading to diseases and disorders which damage the health of these organs and disturb male development. </p>
<h2>Backdoor pathway</h2>
<p>By measuring hormones from blood samples and tissues during the second trimester of human fetal development, this new research helps us understand the pathways driving the production of DHT, and masculinisation of the penis. </p>
<p>It suggests that in addition to the canonical pathway (testosterone from the testis converted to DHT in the GT and driving penis development), male steroids are synthesised by other organs, such as the placenta, liver and adrenal gland via a process called the “backdoor” pathway to contribute to masculinisation. Notably, the backdoor pathway was <a href="https://www.ncbi.nlm.nih.gov/pubmed/12538619">first discovered</a> through research conducted here in Australia on marsupials. </p>
<p>The findings of this research suggest that EDCs might have effects in non-reproductive tissues, including the adrenals and liver, and then cause male reproductive diseases such as hypospadias. </p>
<p>Also, it indicates that placental defects, such as intrauterine growth restriction that results in babies being born small, might contribute to male reproductive diseases in humans. </p>
<p>Further research is now required to follow-up on these interesting findings to explore possible new causal pathways of disorders that begin during pregnancy.</p><img src="https://counter.theconversation.com/content/111625/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dr Mark Green receives funding from the National Health and Medical Research Council, as well as the University of Melbourne for his research on fertility and endocrine disruptors. He is the Secretary for the Society for Reproductive Biology (SRB) and advisor on the effects of endocrine disruptors to the Victorian Assisted Reproductive Treatment Authority (VARTA). </span></em></p><p class="fine-print"><em><span>Andrew Pask receives funding from the Australian Research Council and National Health and Medical Research Council. </span></em></p>Disorders affecting penis development are among the most common birth defects seen in humans, and rates are on the rise.Mark Green, Merck Serono Senior Lecturer in Reproductive Biology, The University of MelbourneAndrew Pask, Professor, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/909712018-02-06T14:07:04Z2018-02-06T14:07:04ZHow the placenta can shed light on HIV mothers and their babies<figure><img src="https://images.theconversation.com/files/204268/original/file-20180131-157477-1dhbsa2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Shutterstock</span> </figcaption></figure><p>In many parts of the world, the human placenta (the after birth) is discarded once a baby is born and considered waste. The focus is on the child and the new mother. </p>
<p>But scientists have started to wake up to the fact that the placenta has many important cells – and that they are able to gain valuable insights into a baby’s development by harnessing modern technologies to understand this transient organ.</p>
<p>A lot is <a href="https://www.ncbi.nlm.nih.gov/pubmed/15507270">known</a> about the placenta already. It starts to develop a few weeks after the egg has been fertilised and the foetus has started to grow. During the pregnancy, as the foetus grows, the placenta develops into a well-structured and highly specialised organ. </p>
<p>As an organ it plays numerous critical roles. It provides the foetus with oxygen, water and nutrients. It ensures all waste products including carbon dioxide are eliminated and it acts as the conduit for hormones like progesterone and estrogen between the mother and the foetus. </p>
<p>But what still remains a mystery is how it develops in HIV positive pregnant women. Several <a href="https://academic.oup.com/jid/article/206/11/1695/896109">studies</a> in sub-Saharan Africa have shown that when a mother-to-be has HIV there is a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3940209/">significant likelihood</a> that she’ll face challenges. This includes stillbirth, a preterm delivery, delivering a baby that is <a href="https://academic.oup.com/humrep/article/27/6/1846/620226">small for its gestational age</a> or having a baby that dies within the first month. If the baby survives, it is likely to be very ill in its first year of life. </p>
<p>This has led scientists to start looking at the placenta to try and gain insight into the effect of HIV on the time of delivery and the health of the newborn babies. </p>
<p>But accessing the placenta isn’t easy. Firstly, it’s difficult to study it at various times of the pregnancy because the unborn child is fully reliant on it and any adjustment could negatively affect the baby. Getting access to the placenta is also a very costly and time consuming exercise. </p>
<p>And lastly early onset of HIV treatment for HIV positive pregnant women makes it hard to tell whether its the actual virus or the treatment that alters the placenta. </p>
<p>But as the only link between the mother and child it is the only avenue to understand the baby’s development.</p>
<p>All this points to why it’s important that novel approaches are used to investigate the link between HIV, treatment regimens, and adverse birth outcomes as well as the effect of HIV on quality of life after birth. </p>
<h2>Next steps</h2>
<p>There are several ways the placenta could be evaluated. One way of understanding the placenta’s role is to look at its cells. It’s home to millions of cells grouped into different cell types. Each cell type plays an important role during pregnancy. </p>
<p>One subset is the regulatory T cells. They regulate how certain systems in the human body function. In a <a href="http://www.jimmunol.org/content/jimmunol/180/8/5737.full.pdf">normal setting</a>, these cells should increase in number during pregnancy. <a href="http://www.jimmunol.org/content/jimmunol/194/4/1534.full.pdf">Research suggests</a> these cells actually migrate from the mothers blood, towards the placenta to ensure that the foetus remains protected. </p>
<p>Research into blood going into the placenta in HIV infected mothers shows that these cells <a href="http://www.bloodjournal.org/content/117/6/1861?sso-checked=true">don’t increase as steadily</a> as in healthy uninfected mothers. That means that the baby is less protected.</p>
<p>A second approach is to evaluate the actual structure and size of the placenta. The average weight of a placenta at 40 weeks is between 500 grams and 700 grams. But, in some cases, the placentas of HIV positive mothers are marginally smaller. The placentas from HIV infected mothers have also been found to have increased inflammation, and develop lesions that block blood supply and oxygen. This may be the underlying reason why the newborns are small for their gestational age. </p>
<h2>Challenges</h2>
<p>There are a number of limitations to studying the placenta. </p>
<p>One of the challenges in studying the placenta of HIV positive women is that most are <a href="http://www.who.int/hiv/PMTCT_update.pdf">now treated</a> as soon as their HIV status is known. This makes it very difficult to tease out whether complications are being caused by the HIV virus or the treatment regimen the mother is taking. </p>
<p>Secondly, research is limited because of the complexity and expense involved in carrying out investigations into placentas </p>
<p>Thirdly, because the unborn child relies on the placenta, it’s difficult to study it without compromising the safety of the baby. This means that placentas are usually evaluated during early pregnancy (first trimester), after an elective abortion or miscarriage or late pregnancy (third trimester), when the baby is born. They are seldom studied during the second trimester. </p>
<p>Despite these limitations, the placenta is an organ that can tell a very interesting story. By investigating the placentas of both HIV infected and uninfected mothers, scientists may be able to get a sneak peek into life inside the womb.</p><img src="https://counter.theconversation.com/content/90971/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nadia Chanzu-Ikumi is an AXA Research Fund fellow.</span></em></p>The placenta could hold the answers to why HIV positive women report higher rates of premature deliveries.Nadia Chanzu-Ikumi, AXA Research Fund-Post doctoral research fellow, Division of Immunology, University of Cape TownLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/864052017-11-15T03:54:37Z2017-11-15T03:54:37ZNo, you shouldn’t eat your placenta, here’s why<figure><img src="https://images.theconversation.com/files/194132/original/file-20171110-29345-1k78od3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Humans and underwater animals are the only mammals that don't eat their placentas.</span> <span class="attribution"><span class="source">from www.shutterstock.com</span></span></figcaption></figure><p>In almost all mammals, the placenta - the organ that develops in pregnancy to provide oxygen and nutrients to the baby and remove waste products - is eaten by the mother immediately after giving birth. Humans and aquatic mammals are the only exceptions. </p>
<p>But the number of women choosing to eat their placenta has <a href="https://www.ncbi.nlm.nih.gov/pubmed/28859955">increased over the past decade</a>.</p>
<p>The most common way to consume the placenta is to have it made into capsules. To do this, the placenta is steamed, dried and then ground into a fine powder. The resulting capsules are taken several times a day during the postpartum period. One placenta usually yields around 100-200 capsules.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/explainer-what-is-placenta-28851">Explainer: what is placenta?</a>
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</em>
</p>
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<h2>Is eating the placenta beneficial?</h2>
<p>Proponents of the practice, which is known as placentophagy, <a href="http://placentabenefits.info/">claim</a> it can <a href="http://www.tandfonline.com/doi/full/10.1080/03670244.2012.719356">boost</a> milk supply, reduce the risk of developing postpartum depression, and replenish vital nutrients. </p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/194133/original/file-20171110-29320-9gi1ci.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/194133/original/file-20171110-29320-9gi1ci.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/194133/original/file-20171110-29320-9gi1ci.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=790&fit=crop&dpr=1 600w, https://images.theconversation.com/files/194133/original/file-20171110-29320-9gi1ci.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=790&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/194133/original/file-20171110-29320-9gi1ci.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=790&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/194133/original/file-20171110-29320-9gi1ci.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=993&fit=crop&dpr=1 754w, https://images.theconversation.com/files/194133/original/file-20171110-29320-9gi1ci.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=993&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/194133/original/file-20171110-29320-9gi1ci.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=993&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Celebrities have claimed eating the placenta has helped with postpartum depression.</span>
<span class="attribution"><span class="source">Screenshot, Instagram</span></span>
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</figure>
<p>To date, there’s no evidence from human studies to support these claims. Most of the proposed benefits are based on <a href="https://www.ncbi.nlm.nih.gov/pubmed/23445390">anecdotal reports</a> from women who have consumed their placentas, and from animal studies.</p>
<p>Nobody knows exactly why non-human mammals eat their placenta. A number of possible explanations have been proposed. <a href="http://www.tandfonline.com/doi/full/10.1080/03670244.2012.661325">According to some scientists</a>, ingestion of the placenta is done to ensure predators are not alerted to the presence of a vulnerable newborn.</p>
<p><a href="http://www.tandfonline.com/doi/full/10.1080/03670244.2012.661325">Others argue</a> the placenta contains useful nutrients and hormones beneficial for a new mother. This idea is also favoured by advocates of human placentophagy.</p>
<p>Two hormones produced by the placenta – prostaglandin and oxytocin – have been identified as <a href="https://www.ncbi.nlm.nih.gov/pubmed/28859955">potential active ingredients in placental capsules</a>. Prostaglandins cause contraction of the uterus, which is important for helping it to return to its pre-pregnancy size. Oxytocin is an essential hormone for promoting milk ejection during lactation.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/ive-always-wondered-whats-behind-the-belly-button-84598">I've always wondered: what's behind the belly button?</a>
</strong>
</em>
</p>
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<p>Unfortunately, there have not been any studies to determine whether the concentrations of these hormones in placenta capsules are high enough to actually induce these beneficial physiological effects.</p>
<p>Many biologically active substances are thought to be lost during the encapsulation process. In one of the few <a href="https://www.ncbi.nlm.nih.gov/pubmed/27324105">published studies</a> investigating the composition of placenta capsules, only three out of the 17 hormones measured in part of the study were present in high enough levels to be physiologically relevant. Notably, two of these hormones – <a href="https://www.drugs.com/breastfeeding/contraceptives-oral-combined.html">oestradiol</a> and <a href="http://jn.nutrition.org/content/131/11/3005S.long">progesterone</a> – can actually <a href="https://www.medscape.com/viewarticle/565623_2">supress milk production</a>. Clearly, more studies are needed to substantiate claims placenta capsules provide hormonal benefits.</p>
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<a href="https://images.theconversation.com/files/194134/original/file-20171110-29374-1fjizfu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/194134/original/file-20171110-29374-1fjizfu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/194134/original/file-20171110-29374-1fjizfu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=848&fit=crop&dpr=1 600w, https://images.theconversation.com/files/194134/original/file-20171110-29374-1fjizfu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=848&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/194134/original/file-20171110-29374-1fjizfu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=848&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/194134/original/file-20171110-29374-1fjizfu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1066&fit=crop&dpr=1 754w, https://images.theconversation.com/files/194134/original/file-20171110-29374-1fjizfu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1066&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/194134/original/file-20171110-29374-1fjizfu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1066&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">The placenta is steamed, dried and crushed into powder form.</span>
<span class="attribution"><span class="source">from www.shutterstock.com</span></span>
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</figure>
<p><a href="https://www.ncbi.nlm.nih.gov/pubmed/22632059">Studies from rats</a> have shown ingestion of the placenta can enhance the effects of opiates naturally produced by the body, that are part of the pain-relief system activated during labour and birth. </p>
<p>The pain-relieving properties come from a unique substance produced by the placenta known as placental opiod-enhancing factor. Like rats, human placentas are also thought to contain the opioid-enhancing factor. </p>
<p>But it’s destroyed by exposure to temperatures above 40°C. Human placentas are usually heated to around 70 °C during the encapsulation process. So it’s very unlikely placenta capsules retain any pain-relieving properties. </p>
<p>Rats also ingest the entire placenta in one sitting immediately after giving birth. This is thought to be important for ensuring they consume enough of the opioid-enhancing factor to gain any benefits.</p>
<p>Some micronutrients, such as iron, are retained during encapsulation. But even though placenta capsules contain high levels of iron, a <a href="https://www.ncbi.nlm.nih.gov/pubmed/27809380">randomised controlled study</a> found there was no difference in iron levels between women who consumed placenta capsules and those who received placebo.</p>
<h2>Is eating the placenta safe?</h2>
<p>The placenta may also be a source of potentially harmful substances.</p>
<p>During pregnancy, the placenta regulates the transfer of substances between mother and baby. As such, accumulation of potentially toxic substances can occur. To date, there have been only a few small studies examining the toxicity profile of placenta capsules. </p>
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<a href="https://images.theconversation.com/files/194136/original/file-20171110-29358-ixpsax.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/194136/original/file-20171110-29358-ixpsax.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/194136/original/file-20171110-29358-ixpsax.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/194136/original/file-20171110-29358-ixpsax.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/194136/original/file-20171110-29358-ixpsax.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/194136/original/file-20171110-29358-ixpsax.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/194136/original/file-20171110-29358-ixpsax.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/194136/original/file-20171110-29358-ixpsax.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">The placenta filters waste products from the baby’s blood, meaning it could potentially contain toxins.</span>
<span class="attribution"><span class="source">from www.shutterstock.com</span></span>
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</figure>
<p>Reassuringly, it’s likely the concentrations of toxins such as lead, mercury, and arsenic are well <a href="https://www.ncbi.nlm.nih.gov/pubmed/27440542">within safe limits</a>. But data is currently available for only a small, select group of elements. There haven’t been any studies to measure the levels of organic pollutants or other potentially harmful substances that may be present in the placenta.</p>
<p>Another concern is that placenta capsules <a href="https://www.cdc.gov/mmwr/volumes/66/wr/mm6625a4.htm">may be contaminated with harmful bacteria</a>. Earlier this year, an infant in the USA was diagnosed with the potentially fatal condition late-onset sepsis, caused by the bacteria group B <em>Streptococcus agalactiae</em>. Placenta capsules consumed by the infant’s mother tested positive for the bacteria, and were identified as a potential source of the infection.</p>
<p>Although reports of infection due to contaminated placental capsules are rare, these cases highlight a potential risk which women should be made aware of. More commonly, <a href="https://www.ncbi.nlm.nih.gov/pubmed/23445390">only mild side effects are reported</a> such as headache, or an unpleasant taste to the capsules.</p>
<p>So given there is no evidence of benefit and some evidence of potential harms, health providers <a href="https://www.ncbi.nlm.nih.gov/pubmed/28859955">should counsel women in their care</a> against consuming their placenta. At the very least, it’s essential all women considering placentophagy are provided with clear, evidence-based information so they can make an informed decision.</p><img src="https://counter.theconversation.com/content/86405/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Bryony McNeill does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Don’t follow the celebs: eating the placenta has no proven benefits, and could be dangerous.Bryony McNeill, Lecturer in Reproductive and Developmental Biology, Deakin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/800742017-06-28T20:10:33Z2017-06-28T20:10:33ZBeing South Asian is as great a risk factor for stillbirth as smoking<figure><img src="https://images.theconversation.com/files/175794/original/file-20170627-21898-6yffki.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">We need to change the way we monitor the pregnancies of women born in South Asia to reduce their chance of a stillbirth.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/456672769?src=ODysdIv-g4OJeDuPHMDNkA-1-30&size=medium_jpg">from www.shutterstock.com</a></span></figcaption></figure><p>Australian women born in South Asia are more likely to have a stillbirth than other women, perhaps due to a rapidly ageing placenta that cannot support the pregnancy, new research suggests.</p>
<p>Our <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5460852/">study</a> looked at 700,000 births in Victoria over more than a decade. We found women born in India, Pakistan, Sri Lanka, Afghanistan and Bangladesh had a 1.5 increased chance of a stillbirth at the end of their pregnancy (known as a “term stillbirth”) compared with women born in Australia or New Zealand.</p>
<p>That’s equivalent to 2.6 term stillbirths per 1,000 births for South Asian-born women compared with 1.5 per 1,000 births to women born in Australia and New Zealand.</p>
<p>This is an increased risk equivalent to <a href="http://www.sciencedirect.com/science/article/pii/S0140673610622337">smoking, advanced maternal age or obesity</a>.</p>
<p>The risk of a term stillbirth increased earlier in pregnancy and rose more rapidly in women born in South Asia. Alarmingly, for South Asian-born women, the rate of stillbirths at 39 weeks’ gestation was almost equivalent to the rate in Australian- and New Zealand-born women at 41 weeks (when the chance of stillbirth would be higher than earlier in the pregnancy).</p>
<p>While other research has found the mother’s ethnicity places a role in the risk of a stillbirth, this has largely been put down to factors related to <a href="http://www.sciencedirect.com/science/article/pii/S014067361501020X">migration and social disadvantage</a>. What our research shows is women born in South Asia and giving birth in Australia are at increased risk even when other factors are taken into account.</p>
<p>This means we need to rethink how we monitor and manage the pregnancies of women born in South Asia, including redefining when some babies reach “term”.</p>
<h2>Why this matters</h2>
<p>About <a href="http://www.aihw.gov.au/WorkArea/DownloadAsset.aspx?id=60129557657">seven per 1,000</a> babies born each year in Australia are stillborn – when the fetus dies at or after 20 weeks’ gestation – a figure that has remained unchanged over the past two decades.</p>
<hr>
<p><em>Further reading: <a href="https://theconversation.com/reducing-the-heartbreak-and-burden-of-stillbirth-1983">Reducing the heartbreak and burden of stillbirth</a></em></p>
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<p>Advanced maternal age, maternal infections, non-communicable diseases (like pre-existing diabetes and high blood pressure), obesity and a prolonged pregnancy are known <a href="http://www.sciencedirect.com/science/article/pii/S014067361501020X">risk factors</a> for stillbirth globally.</p>
<p>Not only can a woman’s country of birth now be added to the list, our research suggests how we look after pregnant women of South Asian origin needs to change.</p>
<p>In another recent <a href="https://www.nature.com/jp/journal/v37/n2/full/jp2016190a.html">study</a>, we found that at 41 weeks’ pregnancy, South Asian-born women experienced rates of fetal distress at almost four times the rate of Australian- and New Zealand-born mothers. </p>
<p>Current <a href="https://www.ranzcog.edu.au/Statements-Guidelines">national</a> and <a href="https://pathways.nice.org.uk/pathways/antenatal-care-for-uncomplicated-pregnancies#content=view-node%3Anodes-pregnancy-after-41-weeks">international</a> guidelines recommend additional fetal monitoring and/or induction of labour for pregnancies that progress beyond 41 weeks due to the increased risks of stillbirth. </p>
<p>But for South Asian-born women this may be too late.</p>
<h2>Why might this be happening?</h2>
<p>There is growing evidence to suggest a mother’s ethnicity influences how fast her <a href="https://theconversation.com/explainer-what-is-placenta-28851?sr=2">placenta</a> ages as her pregnancy progresses.</p>
<p>For some women, they can go into spontaneous labour sooner. In our study, we found South Asian-born women went into labour a median one week earlier than Australian- or New Zealand-born women.</p>
<p>However, for others, an ageing placenta <a href="https://www.ncbi.nlm.nih.gov/pubmed/23452441">cannot meet</a> the fetus’ increasing metabolic needs at term and beyond. And this increases the risk of stillbirth.</p>
<p>We still don’t know which individual woman will go down which path.</p>
<h2>Can we spot ageing placentas?</h2>
<p>Biological markers – caps on the ends of chromosomes or “<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3370421/">telomeres</a>” – can help us assess ageing. Each time a cell replicates, the caps on the chromosomes get shorter. So shorter telomeres are a sign of <a href="http://onlinelibrary.wiley.com/doi/10.1016/j.febslet.2004.11.036/full">more rapid cellular ageing</a>.</p>
<p>And the length of telomeres in placentas from pregnancies ending in stillbirth are <a href="http://www.tandfonline.com/doi/full/10.3109/14767058.2015.1046045">two times shorter</a> than those from live births. In other words, the placental cells had aged faster.</p>
<p>Some researchers have also studied ethnic differences in placental telomere length.</p>
<p>In an <a href="https://www.ncbi.nlm.nih.gov/pubmed/27865975">American study</a>, placental telomeres from pregnancies in black women were significantly shorter than from pregnancies in white women (the ethnic backgrounds of the women were not further defined in the study).</p>
<p>Whether telomeres are shorter in placentas from pregnancies in South Asian-born women is unknown. </p>
<h2>Does this matter?</h2>
<p>We don’t know the cause for up to <a href="http://www.aihw.gov.au/publication-detail/?id=60129557656&tab=3">one-quarter</a> of all stillbirths in Australia. So, better understanding the role of placental ageing may help.</p>
<p>Our research is also relevant as migration from South Asian countries to Australia is <a href="https://www.border.gov.au/ReportsandPublications/Documents/statistics/migration-trends-14-15-glance.pdf">growing</a>. Almost <a href="https://www.border.gov.au/ReportsandPublications/Documents/statistics/2015-16-migration-programme-report.pdf">one-third</a> of people migrating to Australia are from South Asian countries. So, the number of women giving birth in Australia from these countries is also increasing. Now, Indian mothers make up <a href="http://www.aihw.gov.au/publication-detail/?id=60129557656&tab=3">almost 4%</a> (roughly 12,000) of all women giving birth in Australia a year.</p>
<p>It’s time this was reflected in how we manage the pregnancies of women born in South Asia, particularly at the end of their pregnancies. We may have to more closely monitor their pregnancies and, if needed, recommend their labour be induced sooner than other women to reduce their chance of a stillbirth.</p><img src="https://counter.theconversation.com/content/80074/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Miranda Davies-Tuck receives funding from the NHMRC, Stillbirth Foundation and Red Nose Foundation She also has a secondment 1 day per week to Consultative Council on Obstetric and Paediatric Mortality and Morbidity (CCOPMM) at the Victorian Department of Health.</span></em></p><p class="fine-print"><em><span>Euan Wallace receives funding from from the Victorian Government Operational Infrastructure Support Program and is a CEO of Safer Care Victoria, Department of Health.</span></em></p><p class="fine-print"><em><span>Mary-Ann Davey is a part-time employee of the Clinical Councils Unit, which manages the Victorian Perinatal Data Collection data.</span></em></p>Women born in South Asian countries like India or Pakistan are more likely to have a stillbirth than women born in Australia or New Zealand.Miranda Davies-Tuck, Perinatal Epidemiologist and NHMRC Early Career Research Fellow, Hudson InstituteEuan Wallace, Chair professor, Hudson InstituteMary-Ann Davey, Senior Research Fellow, Obstetrics & Gynaecology, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/752192017-04-02T19:27:25Z2017-04-02T19:27:25ZExplainer: what’s cytomegalovirus and why do pregnant women need to know about it?<figure><img src="https://images.theconversation.com/files/162853/original/image-20170328-21254-g451vb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Cytomegalovirus infection in the womb is more common in Australia than infection with listeria or toxoplasma in pregnancy.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/580440025?src=TwN-eTjcWPQZbtH2Fjl_wQ-1-34&size=medium_jpg">from www.shutterstock.com</a></span></figcaption></figure><p><a href="http://journals.sagepub.com/doi/abs/10.1177/1753495X14552719">Cytomegalovirus</a> (CMV) is a virus transmitted from person to person via body fluids like urine or saliva. For people with a healthy immune system, CMV is likely to cause no more than a temporary fever or headache. But when a pregnant woman is infected, the results can be far more serious.</p>
<p>While a pregnant woman herself may not feel sick, the virus can cross the placenta to infect her unborn child and cause permanent disability, including hearing loss and intellectual disability.</p>
<p>In Australia, nearly 2,000 babies are born infected with CMV every year. <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1440-1754.2005.00665.x/abstract">About 380</a> of these are born with permanent disabilities, including deafness, blindness and intellectual disability.</p>
<p>In developed countries, about one in five babies born with CMV will have permanent disabilities. This makes CMV the <a href="http://cmr.asm.org/content/26/1/86.full?sid=f07ec33d-9722-4133-ad4d-0b313d9e9d08">leading infectious cause</a> of disability in newborns in the developed world.</p>
<p>Researchers don’t know the exact mechanism by which CMV can infect the developing baby. But they <a href="http://jvi.asm.org/content/77/24/13301.long">suspect</a> the virus in the pregnant women’s blood first infects the cells of the placenta, where it multiplies and then enters the baby’s circulation via the placenta’s blood vessels.</p>
<p>Researchers also <a href="http://cmr.asm.org/content/22/1/99.long">do not fully understand</a> how CMV then causes hearing loss or intellectual disability. But CMV is thought to directly infect and damage a part of the inner ear. CMV also seems to infect neural stem cells, which are the building blocks of the developing brain. This infection may stop these brain cells from dividing and multiplying, which could affect the size of the baby’s brain and how it matures. CMV infection in the placenta may also prevent the placenta from developing properly. This could reduce the oxygen and nutrients to the baby, which can lead to brain abnormalities.</p>
<h2>Most pregnant women are not aware</h2>
<p>Most pregnant women are unaware of CMV and the simple measures they can take to reduce the chance of contracting this virus.</p>
<p>Studies in <a href="https://bmcpregnancychildbirth.biomedcentral.com/articles/10.1186/s12884-016-0844-9">Canada</a>, <a href="https://www.hindawi.com/journals/idog/2006/080383/abs/">the US</a>, <a href="http://www.journalofclinicalvirology.com/article/S1386-6532(12)00002-9/abstract">France</a>, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4690918/">Switzerland</a>, <a href="https://bmcpregnancychildbirth.biomedcentral.com/articles/10.1186/1471-2393-13-98">the Netherlands</a>, <a href="http://onlinelibrary.wiley.com/doi/10.1111/cga.12030/abstract;jsessionid=CE65575B0BDF8CDEE1FBDC590ED2EB56.f02t04">Japan</a>, and <a href="http://www.sciencedirect.com/science/article/pii/S0020729212000860">Singapore</a> report 61-87% of pregnant women have not heard of the virus. We predict similar rates in Australian pregnant women, although studies to confirm this have not been done yet.</p>
<p>There are no CMV awareness campaigns to provide pregnant women with much needed information about how to protect their baby from CMV, except those run by community organisations, such as in the <a href="http://www.nationalcmv.org">US</a>, the <a href="http://www.cmvaction.org.uk">UK</a> and <a href="http://cmv.org.au/">Australia</a>.</p>
<p>This means, without knowing, many pregnant women are unintentionally putting their baby at risk of CMV infection.</p>
<p>Contrast this with the public awareness of other potentially serious infections in pregnancy, like <a href="https://theconversation.com/health-check-what-to-eat-and-avoid-during-pregnancy-30356">listeriosis</a> (with the advice to avoid soft cheeses, unpasteurised dairy, raw fish and raw meat) and <a href="https://theconversation.com/health-check-what-bugs-can-you-catch-from-your-pets-40954">toxoplasmosis</a> (with the advice to avoid contact with cat faeces).</p>
<p>But in Australia, CMV is now more common than listeriosis and toxoplasmosis in pregnant women. For instance, between 2001 and 2014 there were between <a href="http://www.foodauthority.nsw.gov.au/_Documents/foodsafetyandyou/listeria_and_pregnancy.pdf">one and 14</a> confirmed listeria infections in pregnant women each year. And between 2000 and 2010 there were only <a href="https://www.mja.com.au/journal/2012/196/7/congenital-toxoplasmosis-over-10-years-low-incidence-population">two cases</a> of congenital toxoplasmosis. These data make it clear that more public awareness needs to be raised about CMV infection during pregnancy.</p>
<h2>CMV can be avoided</h2>
<p>The lack of awareness about CMV among pregnant women may be about to change. Recently published <a href="http://thelancet.com/journals/laninf/article/PIIS1473-3099(17)30143-3/fulltext">recommendations</a> from an international team of CMV experts now recommends all pregnant women be told about CMV and what they can do to reduce the risk of contracting it.</p>
<p>Pregnant women can, for instance, contract CMV via intimate contact with young children. This is because CMV can linger in children’s urine and saliva for months after they are infected, while rarely showing symptoms other than a runny nose. </p>
<p>Therefore, good hygiene measures can help avoid contracting CMV. These include:</p>
<ul>
<li><p>not sharing food, drinks or utensils with young children</p></li>
<li><p>not putting a child’s dummy in your mouth</p></li>
<li><p>avoiding contact with saliva when kissing a child</p></li>
<li><p>thoroughly washing your hands with soap and water after changing nappies and after wiping a child’s nose or drool.</p></li>
</ul>
<p>Other precautions pregnant women can take are avoiding sleeping with children and wearing gloves when changing nappies.</p>
<h2>Can CMV be treated?</h2>
<p>At the moment, there is not enough scientific evidence to recommend a therapy to prevent or treat CMV infection during pregnancy.</p>
<p>But scientists are conducting clinical trials to investigate the effectiveness of a CMV vaccine. The first results of these trials are expected between 2017 and 2019. Also, at least one large clinical study is currently on the way to investigate the effectiveness of existing antiviral therapeutics. And scientists are continuing to investigate novel CMV antiviral compounds in the laboratory.</p>
<p>In the meantime, taking the recommended hygiene measures is the best option to prevent CMV infection during pregnancy.</p>
<hr>
<p><em>If you or someone you know is affected by congenital CMV, <a href="http://cmv.org.au/">Congenital CMV Association Australia</a>, the <a href="https://www.nationalcmv.org/">National CMV Foundation</a> in the US and the UK’s <a href="http://www.cmvaction.org.uk">CMV Action</a> provide information and support.</em></p><img src="https://counter.theconversation.com/content/75219/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Wendy van Zuijlen does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>We can prevent congenital deafness and intellectual disability due to cytomegalovirus by simple hygiene measures. So, why don’t pregnant women know about this?Wendy van Zuijlen, Postdoctoral Scientist, Virology Research Laboratory, Faculty of Medicine, UNSW SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/701072017-03-23T14:04:15Z2017-03-23T14:04:15ZUsing the placenta to understand how complex organs evolve<figure><img src="https://images.theconversation.com/files/161653/original/image-20170320-9144-1mig6iy.jpg?ixlib=rb-1.1.0&rect=0%2C6%2C1879%2C1529&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Developing lizard embryo beneath placental tissues.</span> <span class="attribution"><span class="source">Oliver Griffith</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Considering how different they look from the outside, it might be surprising that all vertebrates – animals with a backbone – share the same, conserved set of organs. Chickens, fish, human beings – all have hearts, livers, brains, kidneys and so on. Each of these organs performs a specialized set of functions.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/151484/original/image-20161230-29237-fu9qxn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/151484/original/image-20161230-29237-fu9qxn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/151484/original/image-20161230-29237-fu9qxn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=993&fit=crop&dpr=1 600w, https://images.theconversation.com/files/151484/original/image-20161230-29237-fu9qxn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=993&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/151484/original/image-20161230-29237-fu9qxn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=993&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/151484/original/image-20161230-29237-fu9qxn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1248&fit=crop&dpr=1 754w, https://images.theconversation.com/files/151484/original/image-20161230-29237-fu9qxn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1248&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/151484/original/image-20161230-29237-fu9qxn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1248&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">On the inside, most vertebrates have a similar set of organs, inherited from a common ancestor.</span>
<span class="attribution"><span class="source">Thomas Wallace. Image of display at the National Zoo.</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>How these organs originated and evolved has been a tricky problem to study because of their very ancient origins. The organs we all share must have evolved sometime before the first vertebrates arose on Earth, more than 500 million years ago. And researchers know many of these organs first appeared even earlier. For instance, the <a href="http://news.nationalgeographic.com/news/2014/05/140521-comb-jelly-ctenophores-oldest-animal-family-tree-science/">nervous system may predate the most recent common ancestor</a> of all animals; it’s been identified in invertebrate comb jellies, which split off from all other animals more than 600 million years ago.</p>
<p>To gain insight into how new organs come to be, my colleague and I decided to focus on one that’s more recently evolved – the placenta. It’s a complex organ that has evolved many times independently. In modern animals we see species with no placenta, species with a complex placenta and myriad species between these extremes. <a href="http://www.nature.com/articles/s41559-017-0072">By investigating the evolution of the placenta,</a> my colleague <a href="http://campuspress.yale.edu/wagner/people/">Günter Wagner</a> and I identified several processes that appear fundamental to the evolution of all new organs. </p>
<h2>What’s the placenta’s job?</h2>
<p>In live-bearing animals, the placenta is the organ in the pregnant mother’s body that gives the unborn offspring the raw materials it needs to grow and develop. Made of both parental and embryonic tissue, it supports the exchange of nutrients and gasses between parent and developing embryo.</p>
<p>The first vertebrates, including early mammals, laid eggs and did not have placentas. But in the ancestor of marsupials and eutherian (formerly called placental) mammals, females evolved to hold their eggs inside the uterus until embryonic development was complete. For an embryo to be maintained inside the mother for the duration of pregnancy, it needs a placenta to supply it with oxygen and nutrients, and take away carbon dioxide and other waste products. </p>
<p>Placental structures have evolved to support pregnancy in most organisms that give birth to live young, totaling more than <a href="http://dx.doi.org/10.1002/jez.b.22614">100 independent origins across the animal kingdom</a>. It didn’t happen out of the blue – but what are the steps that result in a new organ? Complex biological structures can evolve via simple changes that build up over time. The process depends on the fact that animals can acquire new body parts and body parts can acquire different functions over multiple generations through successive changes to a species’ DNA. </p>
<h2>New uses and structures for old tissues</h2>
<p>Placentas have evolved across animals in various ways, but always by repurposing existing tissues.</p>
<p>Lizards and snakes provide one example. Most of them lay eggs, but live birth has evolved in this group more than 100 times. In all of these cases, the mother retains the eggs in utero until the offspring are fully developed. In these reptiles, placentas form from the uterus and embryonic membranes that ancestrally <a href="https://theconversation.com/lizards-help-us-find-out-which-came-first-the-baby-or-the-egg-29954">lined the internal surface of the eggshell</a>. That’s how it works in mammals (like us), too.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/151535/original/image-20170102-29222-augh1t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/151535/original/image-20170102-29222-augh1t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/151535/original/image-20170102-29222-augh1t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/151535/original/image-20170102-29222-augh1t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/151535/original/image-20170102-29222-augh1t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/151535/original/image-20170102-29222-augh1t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/151535/original/image-20170102-29222-augh1t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/151535/original/image-20170102-29222-augh1t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Pregnant male seahorse.</span>
<span class="attribution"><a class="source" href="https://pixabay.com/en/seahorse-mollusk-fish-sea-ocean-1742395/">Annunako / Pixabay</a></span>
</figcaption>
</figure>
<p>Live birth happens differently in amphibians and fishes. In guppies, eggs are fertilized and develop inside the ovary before they are ovulated and a placenta is formed <a href="https://theconversation.com/guppies-and-sexual-conflict-its-a-genital-arms-race-14724">from tissues in the ovaries</a>. In seahorses, males develop a <a href="https://theconversation.com/the-secret-sex-life-and-pregnancy-of-a-seahorse-dad-46599">brood pouch on their abdomen</a> and eggs are laid directly into this pouch. The placenta arises from the <a href="https://theconversation.com/genes-reveal-how-the-seahorse-got-its-snout-and-became-a-great-father-70433">father’s belly skin tissue</a>. In the marsupial frog, a <a href="http://doi.org/10.1098/rsbl.2016.0673">pouch develops on the female’s back</a> and a placenta forms from outgrowths of this back skin.</p>
<p>In each of these cases, placentas form when embryonic tissues come into contact with a parental tissue during development. </p>
<p>While placentas have evolved by repurposing existing body parts, sometimes we also see the evolution of entirely new biological structures within these old body parts. <a href="https://doi.org/10.1093/molbev/msv177">Seahorses’ broodpouches</a> are one example, originating evolutionarily after eggs in an ancestor species attached to the underside of the parent’s belly. <a href="http://phys.org/news/2015-11-evolution-cell.html">New specialized cell types</a> can evolve, too, to perform new functions.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/151554/original/image-20170102-18650-berz80.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/151554/original/image-20170102-18650-berz80.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=269&fit=crop&dpr=1 600w, https://images.theconversation.com/files/151554/original/image-20170102-18650-berz80.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=269&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/151554/original/image-20170102-18650-berz80.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=269&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/151554/original/image-20170102-18650-berz80.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=339&fit=crop&dpr=1 754w, https://images.theconversation.com/files/151554/original/image-20170102-18650-berz80.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=339&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/151554/original/image-20170102-18650-berz80.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=339&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Placentas have evolved many times independently in various animals. They form following the interaction of parental (red) and embryonic (blue) tissues.</span>
<span class="attribution"><span class="source">Oliver Griffith</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>When tissues take on a new job</h2>
<p>So in the case of the placenta, the evolution of a new organ involved repurposing existing tissues. These tissues had functions in the ancestor of the placental animal, some of which have been recruited to support the new organ functions. </p>
<p>One example of this is hormone production in embryonic membranes. In egg-laying terrestrial vertebrates, eggs are lined with a series of membranes. These embryonic membranes <a href="https://theconversation.com/pregnancy-cooperative-paradise-or-conflict-driven-battle-between-mother-and-child-58564">produce a diversity of hormones</a>, which are likely important for the growth and development of the fetus. Following the evolution of live birth, the hormones were able to interact with maternal tissues, resulting in the evolution of fetal-maternal communication.</p>
<p>Prior research has shown that <a href="https://www.ncbi.nlm.nih.gov/books/NBK9983/">signaling between distinct tissues</a> is typically how organ development is initiated in animals. We suspect that this signaling was important not just for the organ’s development, but for how it originated. </p>
<p>If a mutation results in tissues developing alongside each other in a new way, then the signaling dynamics inside these tissues are likely to affect each other’s development. This new signaling can then be an initiator for the development of a new organ. </p>
<p>We think the placenta is just one example of this phenomenon in action. This path may be a general way in which new organs arise in animals.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/151547/original/image-20170102-18647-1ngh8m3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/151547/original/image-20170102-18647-1ngh8m3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/151547/original/image-20170102-18647-1ngh8m3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/151547/original/image-20170102-18647-1ngh8m3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/151547/original/image-20170102-18647-1ngh8m3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/151547/original/image-20170102-18647-1ngh8m3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/151547/original/image-20170102-18647-1ngh8m3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/151547/original/image-20170102-18647-1ngh8m3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Pregnancy in eutherian mammals, which include humans, has required the evolution of a new cell type in the uterus.</span>
<span class="attribution"><a class="source" href="https://pixabay.com/en/pregnancy-panza-barriga-mama-1677333/">TC-TORRES / Pixabay</a></span>
</figcaption>
</figure>
<h2>Placenta’s evolution as a case study</h2>
<p><a href="http://www.nature.com/articles/s41559-017-0072">Our research suggests</a> that new organs evolved by repurposing existing body parts. Over evolutionary time, organs can evolve new structures and new functions that increase the fitness or reproductive success of the animal. These changes result from genetic alterations that we can identify by comparing living animals.</p>
<p>An individual animal doesn’t all of a sudden have an organ that’s never been seen before. But small genetic changes happen all the time. As they accumulate, eventually, complex biological structures can evolve. Now we’re starting to identify specific types of genetic changes that allow for new complex organs to evolve inside animals.</p><img src="https://counter.theconversation.com/content/70107/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Oliver Griffith receives funding from Yale Institute for Biospheric Studies. </span></em></p>Taking the placenta as a case study, researchers are able to piece together how new organs evolve, by repurposing old tissues and using them to do new jobs.Oliver Griffith, Postdoctoral Associate in Ecology and Evolutionary Biology, Yale UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/639982016-08-18T18:49:52Z2016-08-18T18:49:52ZA pregnant woman’s immune response could lead to brain disorders in her kids<p>Pregnant women, like everyone, get sick. And like everyone else, their bodies try to fight infection and, importantly, keep it from reaching the growing fetus. </p>
<p>If the mother’s immune system successfully defeats the virus before the developing baby is exposed or if the virus never crosses the placenta, is harm averted? </p>
<p>Counterintuitively, this protective response may be a risk factor for some neurological conditions in the baby later on.</p>
<p>This is the question that researchers, including me, have been probing at the neurodevelopment lab at the University of California, Davis. Research suggests that the mother’s defensive immune response to an infection, for instance, alone is sufficient to <a href="http://dx.doi.org/10.1016/j.pharmthera.2015.01.001">cause lifelong changes</a> in brain architecture and function and in behavior in the offspring. This response is a strong risk factor for brain disorders like <a href="http://dx.doi.org/10.1016/j.bbr.2008.12.016">autism and schizophrenia</a>.</p>
<p>Kimberley McAllister, who leads the neurodevelopment lab, and I reviewed recent research about what is called maternal immune activation (MIA) in humans and in animals in an article published today in <a href="http://dx.doi.org/10.1126/science.aag3194">Science</a>. So what do we know so far about MIA and where research is headed?</p>
<h2>What is maternal immune activation?</h2>
<p>Maternal immune activation refers to the mother’s immune system defensive response to invading pathogens. During pregnancy the immune system changes to accommodate the needs of the growing fetus. These changes are complex and depend on her stage of pregnancy and the pathogens she encounters. The intensity of the immune response is highly individualized and represents a complex interaction between the mother’s genes and environment.</p>
<p>A study in humans has <a href="http://dx.doi.org/10.1542/peds.2012-1107">suggested</a> that the degree and duration of MIA determines the risk of a child being diagnosed with a brain disorder later on, like autism or schizophrenia. And infections aren’t the only cause of MIA. For example, an increased risk is also associated with <a href="http://dx.doi.org/10.1016/j.yhbeh.2012.03.007">psychological stress</a> during pregnancy, which triggers a similar immune activation. </p>
<p>Studies like these identify associations, but not causation. However, animal studies support a causal role for these risk factors and are beginning to reveal the underlying mechanisms. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/134658/original/image-20160818-12292-kb8n39.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/134658/original/image-20160818-12292-kb8n39.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=434&fit=crop&dpr=1 600w, https://images.theconversation.com/files/134658/original/image-20160818-12292-kb8n39.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=434&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/134658/original/image-20160818-12292-kb8n39.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=434&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/134658/original/image-20160818-12292-kb8n39.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=545&fit=crop&dpr=1 754w, https://images.theconversation.com/files/134658/original/image-20160818-12292-kb8n39.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=545&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/134658/original/image-20160818-12292-kb8n39.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=545&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">What’s going on?</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-140518024/stock-photo-obstetric-ultrasound-of-fetus-at-fourth-month-echography-scan.html?src=OSK7IPwaaTzXRkJ2QprP6w-1-9">Ultrasound image via www.shutterstock.com.</a></span>
</figcaption>
</figure>
<h2>Why does MIA increase the risk of brain disorders?</h2>
<p>Every pathogen has its own unique signature and trick up its sleeve to subvert the body’s defenses. However, at least during the first days of infection, the immune system initiates a standard response. We are all familiar with its consequences: fever, lethargy, aches and pains.</p>
<p>While the body weathers these symptoms, the immune system is hard at work deploying communicative proteins called cytokines, which tell immune cells where to go and how to destroy invading pathogens.</p>
<p>During an infection, the concentrations of cytokines change rapidly in order to guide the immune response. Too little and you succumb to the pathogen; too much and you <a href="http://dx.doi.org/10.1038/cmi.2015.74">die of sepsis</a>. And besides telling immune cells where to go and what to do, cytokines have also been shown to play integral roles in <a href="http://dx.doi.org/10.1016/j.neuron.2009.09.002">brain development</a> in animal models.</p>
<p>During pregnancy, the mother’s cytokines can affect the fetus.</p>
<p>In the developing brain, the concentration of cytokines is tightly regulated. Here, too little or too much, in the wrong place or at the wrong time, can alter the architecture and function of the developing brain. </p>
<p>While the full repertoire of these changes are unknown, studies using animals have shown that altering cytokine concentrations changes how brain regions are connected to one another and how they communicate. These types of alterations in specific areas of the brain are thought to underlie numerous brain disorders. </p>
<p>Our lab has <a href="http://dx.doi.org/10.1016/j.bbi.2012.07.008">shown</a> that these cytokine changes in the fetal brain are lifelong and region-specific. Another <a href="http://dx.doi.org/10.1126/science.aad0314">recent paper</a> showed that a greater concentration of a specific cytokine, IL-17, within the fetal brains of mice was sufficient to lead to brain changes, which resulted in altered behaviors associated with autism and schizophrenia. Cytokine changes are also associated with another indicator of brain disorders: <a href="http://dx.doi.org/10.1523/JNEUROSCI.2366-13.2013">alterations</a> in the number of connections made between neurons. </p>
<p>Whether or not these cytokine changes are a cause of these disorders in humans remains to be seen. But there is evidence from post-mortem brain samples taken from individuals with <a href="http://www.ncbi.nlm.nih.gov/pubmed/15546155">autism</a> and <a href="http://dx.doi.org/10.1038/mp.2016.90">schizophrenia</a> that show altered concentrations of cytokines.</p>
<p>The ultimate goal is to identify a cytokine profile that predicts certain behaviors and neurological disorders in animals. In the future, we could potentially use this profile to identify biomarkers of specific brain disorders in people. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/134656/original/image-20160818-12318-1bgh2ot.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/134656/original/image-20160818-12318-1bgh2ot.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=420&fit=crop&dpr=1 600w, https://images.theconversation.com/files/134656/original/image-20160818-12318-1bgh2ot.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=420&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/134656/original/image-20160818-12318-1bgh2ot.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=420&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/134656/original/image-20160818-12318-1bgh2ot.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=528&fit=crop&dpr=1 754w, https://images.theconversation.com/files/134656/original/image-20160818-12318-1bgh2ot.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=528&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/134656/original/image-20160818-12318-1bgh2ot.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=528&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Human brain cells.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/wellcomeimages/5814146087/in/photolist-9RM254-qQ9W4e-qJfENo-rxtGPM-a86uJv-oEdnfk-kh2FWg-poJjr3-bGTZvH-btZbT7-a89QkW-btZbXb-a86zcZ-4QguVR-4QgsFX-bGTZ66-9RQtYo-a89QnE-rg2f7A-9RMzep-9RQtU7-9RMzfp-9RMyJ2-9RMyDr-btZbJS-7fo2JQ-rxzEAv-btZcaN-a86PF2-kh6urL-4QguHP-4QkHwA-9RPVzh-bGTZrB-9RQtN7-bGTZ6T-4Qgsye-4QkHkA-a86Qbr-kh1X9V-HdBJjT-J6sKm7-HdBJkK-HHWQNQ-HdBJsD-HdBJvV-J6sKzo-HHWQV3-FkJj25-HdBJuT">Spike Walker, Wellcome Images</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<h2>MIA, genetics and environment</h2>
<p>Over the past decade, hundreds of genes have been associated with a wide range of brain disorders. However, each of these genes increases risk only slightly. Any number of combinations of the associated genes may result in a brain disorder such as autism.</p>
<p>To us, research suggests that the maternal infection acts as a disease primer. In other words, maternal immune activation may make the fetus more susceptible to genetic and environmental risk factors.</p>
<p>Hypothetically, if the fetus experiences a low dose of MIA, and as an adolescent experiences <a href="http://dx.doi.org/10.1126/science.1228261">stress</a> or uses <a href="http://dx.doi.org/10.5402/2012/451865">cannabis</a>, the combination might trigger brain changes that could lead to schizophrenia. </p>
<p>Researchers are just starting to explore how genetic and environmental risk factors combine with MIA. These studies will help to explain why the outcomes of MIA are so diverse. The good news is that the majority of cases do not lead to any observable disorders.</p>
<p>While this may sound like a daunting challenge, important progress is being made. For example, many of the genes we know to be associated with certain conditions appear to be related to one another in how they function in the brain, which gives us insight into what brain processes are disrupted when people have these disorders. </p>
<p>This may explain the role cytokines play in raising risk for these disorders. They transmit messages from one cell or tissue to another, triggering numerous changes within the receiving cell. The processes and pathways in the brain that cytokines may disrupt may be the same processes and pathways that the risk genes disrupt as well. </p>
<p>If this is the case, it suggests we may be able to develop new therapeutics that benefit individuals with different disorders, regardless of whether the cause of the disorder is primarily environmental, like a maternal infection, or genetic. </p>
<h2>Where is this research headed?</h2>
<p>Numerous questions remain unanswered in our field. Why do only some children born to women who experience MIA go on to develop these disorders? How can we identify high-risk pregnancies? What combination of genetics and environmental risk factors distinguish autism from schizophrenia or Alzheimer’s? </p>
<p>All of these questions are currently being explored using animals, and the initial findings are both astounding and hopeful. For example, some behavioral features of these disorders can be prevented with <a href="http://dx.doi.org/10.1038/tp.2016.38">early intervention</a> or even <a href="http://dx.doi.org/10.1186/2040-2392-6-1">reversed</a> autism-like disorders in adulthood.</p>
<p>Moreover, some of these interventions are noninvasive and involve altering gut <a href="http://dx.doi.org/10.1016/j.cell.2013.11.024">microbiota</a> and immune system signaling. Whether or not similar approaches will work in humans remains to be seen. </p>
<p>If MIA does indeed act as a disease primer for a wide range of brain disorders, it is imperative that we identify groups at higher risk and develop therapeutic interventions. Climate change, population growth and urbanization all increase the risk of exposure to pathogens. The social, economic and emotional tolls are too substantial to ignore. </p>
<p>MIA risk has always been there. It is only our understanding that is new. By studying MIA, we may now begin to reveal common principles underlying seemingly disparate brain disorders. And most hopefully, we may harness these insights to increase our resilience.</p><img src="https://counter.theconversation.com/content/63998/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Myka Estes receives support from Autism Speaks, the Achievement Rewards for College Scientists Foundation, University of California Office of the President, University
of California Davis Research Investments in Science and
Engineering Program, the National Institute of Neurological Disorders and Stroke, the National Institute of Mental Health, and the Simons Foundation </span></em></p>A pregnant woman’s immune response may be a risk factor for some neurological conditions like autism and schizophrenia in the baby later on.Myka Estes, Postdoctoral Researcher in Neuroscience , University of California, DavisLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/585642016-05-05T17:04:09Z2016-05-05T17:04:09ZPregnancy: cooperative paradise or conflict-driven battle between mother and child?<figure><img src="https://images.theconversation.com/files/121263/original/image-20160504-19860-5hzt01.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">There's a battle for resources going on in there.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/cglatz/12582433">Christian Glatz</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>Pregnancy sounds like the ultimate form of animal cooperation – mothers share their own bodies to grow and support their children’s prenatal development. But in reality, embryos use every trick in the book to take more than their fair share. Mothers, in turn, marshal their best defensive tactics.</p>
<p>Ultimately, it’s an evolutionary arms race. Offspring continually evolve strategies to steal resources, while mothers evolve strategies to defend their resources. Natural selection will favor embryos that are able to steal resources, but this will impose costs on the mother.</p>
<p>My colleagues and I are interested in how the mechanisms of this battle could have evolved. We recently investigated some differences between closely related animals that carry their young and others that lay eggs to figure out how hormones evolved to be expressed in the placenta. By understanding the processes that support conflict, we can identify how this conflict arose, and the impacts that it might hold for human health.</p>
<h2>Placenta as a combat zone</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/121264/original/image-20160504-5832-p6fwyo.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/121264/original/image-20160504-5832-p6fwyo.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/121264/original/image-20160504-5832-p6fwyo.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=619&fit=crop&dpr=1 600w, https://images.theconversation.com/files/121264/original/image-20160504-5832-p6fwyo.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=619&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/121264/original/image-20160504-5832-p6fwyo.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=619&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/121264/original/image-20160504-5832-p6fwyo.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=777&fit=crop&dpr=1 754w, https://images.theconversation.com/files/121264/original/image-20160504-5832-p6fwyo.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=777&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/121264/original/image-20160504-5832-p6fwyo.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=777&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The placenta allows mother and embryo to exchange resources.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Placenta#/media/File:Placenta.svg">Gray's Anatomy of the Human Body</a></span>
</figcaption>
</figure>
<p>During pregnancy, mothers support their offspring by providing nourishment across a <a href="https://en.wikipedia.org/wiki/Placenta">placenta</a>. Formed from both the embryo’s and mother’s tissue, this organ facilitates the exchange of materials between the two. The placenta is responsible for transferring oxygen and nutrients to the baby, while taking away waste products like carbon dioxide and urea.</p>
<p>By secreting hormone signals across the placenta to be received by the mother’s body, embryos can alter the amount of food they’re provided. In a truly cooperative world, offspring would release these “gimme more!” hormones only if they were undernourished. But embryos actually produce these hormones demanding more of the mother almost constantly throughout pregnancy. </p>
<p>Mothers’ bodies fend off these hormonal demands with defenses including the development of physical barriers between the embryo and the maternal blood supply, and the production of enzymes that can break down excessive levels of embryo-produced hormones.</p>
<p>But where did the tools embryos use to wage this battle come from? That’s the question my colleagues and I recently investigated.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/120431/original/image-20160428-30990-1svmtax.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/120431/original/image-20160428-30990-1svmtax.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/120431/original/image-20160428-30990-1svmtax.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/120431/original/image-20160428-30990-1svmtax.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/120431/original/image-20160428-30990-1svmtax.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/120431/original/image-20160428-30990-1svmtax.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/120431/original/image-20160428-30990-1svmtax.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/120431/original/image-20160428-30990-1svmtax.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Embryo of a southern grass skink, a live-bearing reptile.</span>
<span class="attribution"><span class="source">Oliver Griffith</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Hunting for the origins of the conflict</h2>
<p>Placentas are not limited to mammals. They’re also found in <a href="https://theconversation.com/lizards-help-us-find-out-which-came-first-the-baby-or-the-egg-29954">reptiles</a> and fishes like the <a href="https://theconversation.com/the-secret-sex-life-and-pregnancy-of-a-seahorse-dad-46599">seahorse</a>. </p>
<p>In recent research published in the journal <a href="http://doi.org/10.1016/j.ygcen.2016.04.017">General and Comparative Endocrinology,</a> my collaborators and I aimed to identify how an animal species evolves a placenta. </p>
<p>We know that live-bearing animals evolve from egg-laying ones, but we were curious about the role of parent-offspring conflict in this process. Did placental control of pregnancy evolve via novel hormones? Or did it rely on genes that were already present in the ancestral populations?</p>
<p>Our first step was examining the hormones produced by the placental tissue of three animal species: the horse, the <a href="http://www.parks.tas.gov.au/indeX.aspX?base=5421">southern grass skink</a> lizard and a live-bearing population of the <a href="https://museumvictoria.com.au/discoverycentre/infosheets/lizards-found-in-victoria/bougainvilles-skink/">southeastern slider lizard</a>.</p>
<p>We know each of these groups evolved pregnancy independently, because each is more closely related to an egg-laying species than they are to each other. For example, the first mammals were egg-laying and some of them are still around today – Australia’s platypus, for instance. Similarly, each of the live-bearing lizard species we studied has closely related egg-laying relatives.</p>
<p>By studying both the live-bearing and egg-laying relatives of these animals we can understand the things that are necessary for the transition. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/120433/original/image-20160428-30979-e1n1ok.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/120433/original/image-20160428-30979-e1n1ok.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/120433/original/image-20160428-30979-e1n1ok.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/120433/original/image-20160428-30979-e1n1ok.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/120433/original/image-20160428-30979-e1n1ok.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/120433/original/image-20160428-30979-e1n1ok.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/120433/original/image-20160428-30979-e1n1ok.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/120433/original/image-20160428-30979-e1n1ok.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The southeastern slider has live-bearing and egg-laying varieties.</span>
<span class="attribution"><span class="source">Jordan de Jong</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>We compared the list of hormones produced by these animals’ placental tissues to a similar tissue from two egg-laying animals: the chicken and an egg-laying population of the southeastern slider lizard. These species don’t have placentas because they lay eggs rather than carrying their unborn young internally. But placentas evolved from a membrane that lines the internal surface of developing eggs. This embryonic membrane supports the exchange of gasses between the embryo and the world outside its egg.</p>
<p>When we compared the genes found in the embryonic membrane of species with and without a placenta, the lists largely matched. This finding shows that the hormones used by embryos to manipulate their mothers evolved a long time ago, in an ancestor of both reptiles and mammals. When pregnancy evolved, the mechanisms to initiate conflict between the mother and embryo were already in place. </p>
<p>While we don’t know the function of these hormones in egg-laying species, we can speculate. The embryonic membrane is the first living point of contact between an embryo and the outside world. These hormones may alter the development of embryos in response to some environmental stimulus, such as temperature or disease.</p>
<h2>Mom vs. dad at the placenta battlefield</h2>
<p>Why are mothers and embryos at odds, anyway?</p>
<p>After all, animals have two major evolutionary goals: to survive and to produce fertile offspring to spread their genes. Individuals maximize the fitness of their genes by producing as many healthy offspring as they can over their lifetime. So it seems reasonable that mothers would want to support their offspring to give them the best chance of survival – as long as it doesn’t put mom herself at risk.</p>
<p>But remember, offspring contain genes from both parents. If a father can alter the development of his offspring in a way that allows it to take advantage of the mother, even if it imposes a cost on her, it would give him and his genes a fitness advantage. </p>
<p>This is particularly critical when females mate with multiple males. In this case, a father may be the parent of just one or a few of the many offspring a female produces over her lifetime. He wants his offspring to have an edge over others fathered by competitors.</p>
<p>In this way, the goals of the father’s genes may not overlap with the goals of the mother’s. It’s the differences between the goals of the mom and dad genes that are the ultimate cause of mother-embryo conflict during pregnancy.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/120442/original/image-20160428-30967-1hqadwa.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/120442/original/image-20160428-30967-1hqadwa.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/120442/original/image-20160428-30967-1hqadwa.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/120442/original/image-20160428-30967-1hqadwa.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/120442/original/image-20160428-30967-1hqadwa.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/120442/original/image-20160428-30967-1hqadwa.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/120442/original/image-20160428-30967-1hqadwa.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/120442/original/image-20160428-30967-1hqadwa.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Pregnant southern grass skink, site of mother-embryo conflict.</span>
<span class="attribution"><span class="source">Jacquie Herbert</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Ways to control development beyond genes</h2>
<p>As a result of the ongoing battle across the placenta, some animals have evolved strategies to affect the development of their children in ways that do not include changes to the genes they pass on. </p>
<p>For instance, males and females can mark the genes of their sperm and eggs in different ways so the effect of the gene depends on which parent passed it on. Scientists call this phenomenon – when a gene’s outcome in an individual depends on whether it was inherited from the mother or father – genomic imprinting.</p>
<p>Genomic imprinting is one mechanism by which the placenta battle can be waged. </p>
<p>The gene that produces insulin like growth factor two (<a href="https://ghr.nlm.nih.gov/gene/IGF2">IGF2</a>) is an example. It controls placental growth: more of the hormone results in a bigger placenta and more nutrients being transferred to the offspring, while lower production results in smaller offspring. </p>
<p>When the mother makes egg cells, she modifies the IGF2 gene by adding molecules that ultimately change the structure of DNA. With this alteration, the genes encoded by the DNA cannot be expressed. So in normal offspring, the maternal copy of this gene isn’t expressed, while the paternal copy is. Mom is working to make sure the embryo doesn’t greedily take more resources than it needs, while Dad is happy to see the embryo garner more than strictly necessary.</p>
<p>My research group wanted to identify whether genomic imprinting is present in the reptiles that have a placenta. In research published in the journal <a href="http://doi.org/10.1007/s00427-016-0531-x">Development Genes and Evolution,</a> we looked at the genes that are imprinted in the placenta of mammals, and checked for imprinting of those same genes in the southern grass skink.</p>
<p>It turned out none of the mammalian imprinted genes are imprinted in this lizard, suggesting some fundamental differences between the role of conflict in mammalian and reptile pregnancy. The war in mammal placentas is waged using genomic imprinting, where as in reptiles, it appears that mothers and fathers must use other tools.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/FYYvOl9PYhs?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Female southern grass skink giving birth. After delivery, the mother can be seen eating the placental tissues.</span></figcaption>
</figure>
<p>Together our studies suggest that the genes responsible for conflict in animals that exhibit pregnancy were present in the embryonic membranes of the most recent common ancestor of mammals and reptiles, which lived more than 300 million years ago. It looks like conflict between mother and child is baked into species, and is likely to occur anytime pregnancy evolves in animals.</p>
<p>While the processes that underpin conflict are well understood, many questions remain. How does the process of conflict contribute to the evolution of a complex organ like a placenta? I’m interested in how this internal conflict interacts with the environment in natural ecosystems. For example, how does the availability of resources affect how the mother provides those resources to her offspring? My ongoing research seeks to understand how resource availability affects what embryos receive through the placenta, and the genetics that underpin this organ’s function.</p><img src="https://counter.theconversation.com/content/58564/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Oliver Griffith receives funding from Australian Society of Herpetologists and the Gaylord Donnelley Postdoctoral Environmental Fellowship.</span></em></p>Embryos greedily want more resources than their fair share. New research investigates how early in evolution their hormonal tactics arose.Oliver Griffith, Postdoctoral Associate in Ecology and Evolutionary Biology, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/288512015-04-08T04:36:31Z2015-04-08T04:36:31ZExplainer: what is placenta?<figure><img src="https://images.theconversation.com/files/77271/original/image-20150408-26476-1iomi3b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The placenta plays a critical role in pregnancy, fetal development and health throughout life</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/remysharp/6196105213">Remy Sharp/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>An incredibly complex and important organ in its own right, the placenta is only found in mammals. And how it functions has the potential to have profound effects on the lifelong health of the developing foetus. </p>
<p>The placenta exists solely during pregnancy, and plays a crucial role in nurturing and protecting the foetus throughout gestation. It’s connected to the foetus via the umbilical cord and attached to the wall of the womb, allowing for essential exchanges of nutrients, gases and waste with the mother’s circulation. </p>
<p>Placenta is composed of maternal and foetal parts, which are known as the basal and chorionic plates, respectively. Nutrients are exchanged through the maternal blood entering the foetal section, but maternal and foetal blood don’t actually mingle; they’re separated by arteries and capillaries. </p>
<p>Interestingly, <a href="http://www.ncbi.nlm.nih.gov/pubmed/20004469">the placenta has a gender</a> matching that of the foetus, indicated with the presence of either XX or XY sex chromosomes. But placental sex is not used to test fetal gender as that would require invasive surgical tests and add unnecessary risk to the pregnancy. </p>
<h2>In the beginning</h2>
<p>The placenta begins developing once the embryo is implanted into the wall of the uterus. During the nine months of pregnancy, it increases in size and performs several vital functions. It regulates the <a href="http://www.ncbi.nlm.nih.gov/pubmed/25009498">exchange of nutrients</a> for foetal growth and development, the exchange of gases including oxygen and carbon dioxide, and hormone secretion. </p>
<p>It also protects the foetus from toxins and infections as well as the <a href="http://www.ncbi.nlm.nih.gov/pubmed/24581729">mother’s immune system</a>, which would otherwise regard it as a foreign invader. This is a critical aspect of placental physiology; if the mother’s immune system rejects the foetus, it will spontaneously abort.</p>
<p>In order to prepare the developing foetus for the world it will inhabit after pregnancy, the placenta is very sensitive to the mother’s environment. It’s able to adjust its functions in response to external cues, such as the mother’s diet or environmental pollutants, which can then alter foetal development. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/77277/original/image-20150408-26515-5ut8qi.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/77277/original/image-20150408-26515-5ut8qi.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/77277/original/image-20150408-26515-5ut8qi.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/77277/original/image-20150408-26515-5ut8qi.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/77277/original/image-20150408-26515-5ut8qi.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/77277/original/image-20150408-26515-5ut8qi.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/77277/original/image-20150408-26515-5ut8qi.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The placenta begins developing once the embryo is implanted into the wall of the uterus.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/louisewoodcock/5151401966">Louise Woodcock/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p><a href="http://www.ncbi.nlm.nih.gov/pubmed/25222554">Maternal diet</a> plays a major role in foetal development; studies show eating a balanced diet of fruit, vegetables, and lean meat <a href="http://www.ncbi.nlm.nih.gov/pubmed/25551251">helps reach a good birth weight</a>. But <a href="http://www.ncbi.nlm.nih.gov/pubmed/19221603">exposure to pollutants</a>, such as car exhaust fumes, can have a negative impact and may increase the risk of the child developing asthma. </p>
<p>Permanent changes to the developing foetus’s physiology during development is known as foetal <a href="http://www.ncbi.nlm.nih.gov/pubmed/11978056">programming</a>. And variations in the development of organs and systems within the foetus may increase lifetime susceptibility to <a href="http://www.ncbi.nlm.nih.gov/pubmed/25724893">cancer</a>, <a href="http://www.ncbi.nlm.nih.gov/pubmed/24817102">heart disease</a>, <a href="http://www.ncbi.nlm.nih.gov/pubmed/12750609">allergies</a> and other diseases. </p>
<p>The mechanisms underlying these susceptibilities are incredibly complex and we’re only now beginning to understand them. One of them is <a href="http://www.ncbi.nlm.nih.gov/pubmed/24835110">epigenetics</a>, which changes foetal gene expression, altering the physiology and functioning of the foetus throughout life.</p>
<h2>What can go wrong</h2>
<p>Placental disorders can cause <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1651-2227.1997.tb18405.x/abstract">serious health complications</a> during pregnancy for both the foetus and mother. They can result in abnormal foetal development, growth restriction, malformations, miscarriage or stillbirth, and may even <a href="http://www.ajog.org/article/0002-9378(93)90043-I/abstract">endanger the mother’s life</a>.</p>
<p>Because the placenta keeps forming throughout pregnancy, <a href="http://www.ncbi.nlm.nih.gov/pubmed/17007686">abnormalities</a> in its structure and implantation into the uterine wall can happen at any time. <a href="http://www.ncbi.nlm.nih.gov/pubmed/24836826">Placental abruption</a>, for instance, occurs in approximately one in a 100 pregnancies. Abruption is either the partial or full detachment of the placenta from the uterine wall. And it can deprive the foetus of oxygen and nutrients, potentially leading to preterm birth or stillbirth. </p>
<p>One of the <a href="http://www.ncbi.nlm.nih.gov/pubmed/25750742">most common disorders</a> of pregnancy is <a href="http://www.ncbi.nlm.nih.gov/pubmed/25767405">pre-eclampsia</a>, which occurs in 3% to 7% of all pregnancies; it’s the leading cause of maternal health complication and death. Characterised by high blood pressure and protein in the urine, pre-eclampsia can lead to permanent vascular and metabolic damage in the mother. </p>
<p>The exact cause of the disorder is unknown, but it’s thought several factors including poor diet, high body fat, a history of high blood pressure and genetics may all play a role. Abnormal placental development and function is thought to be another major contributing factor.</p>
<p>If left untreated, pre-eclampsia can develop into <a href="http://www.ajog.org/article/0002-9378(90)91176-D/abstract?cc=y">eclampsia</a>, which is characterised by cerebral fluid build-up and seizures. Once the placenta is removed, pre-eclampsia and eclampsia end. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/77273/original/image-20150408-26476-7i15dd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/77273/original/image-20150408-26476-7i15dd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=392&fit=crop&dpr=1 600w, https://images.theconversation.com/files/77273/original/image-20150408-26476-7i15dd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=392&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/77273/original/image-20150408-26476-7i15dd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=392&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/77273/original/image-20150408-26476-7i15dd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=493&fit=crop&dpr=1 754w, https://images.theconversation.com/files/77273/original/image-20150408-26476-7i15dd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=493&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/77273/original/image-20150408-26476-7i15dd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=493&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Out of the several thousand mammalian species, humans are among only a handful that don’t regularly consume the placenta.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/kom_bo/3179203175/in/photostream/">Kom bo/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>The placenta can become infected by bacteria, viruses or <a href="http://trstmh.oxfordjournals.org/content/77/2/232.short">parasites</a> which can lead to abnormal foetal development, preterm birth or foetal death. This occurs mostly in developing countries such as Africa, where <a href="http://www.placentajournal.org/article/S0143-4004(03)00307-2/abstract">the malaria parasite</a> contributes to 100,000 deaths annually as a result of severe foetal growth restriction.</p>
<p>Finally, cancer of the placenta, known as choriocarcinoma, occurs in approximately one in 20,000 to 40,000 pregnancies. This cancer usually spreads to lungs and while it can be life-threatening, the cure rate is over 90%. It’s very responsive to <a href="http://onlinelibrary.wiley.com/doi/10.1046/j.1525-1438.2002.01125.x/full">chemotherapy</a>, which is given after the baby is born.</p>
<h2>Cultural significance</h2>
<p>The placenta has little cultural value in Western countries; it’s often unrecognised by parents as being fundamental for a healthy and successful pregnancy. So, it’s usually discarded after childbirth. </p>
<p>But some other cultures hold great respect for this uniquely temporary organ, and have the mother eat it, in a practice known as <a href="http://www.bbc.com/news/uk-england-27307476">human placentophagy</a>. According to traditional <a href="http://www.natureofbirth.com.au/placenta-bar.html">Chinese medicine</a>, for instance, the placenta is thought to rejuvenate the body after childbirth. </p>
<p>This practice has recently become more popular in Western culture but remains highly controversial, mostly due to the cannabalistic nature of the act. There are few <a href="http://www.tandfonline.com/doi/abs/10.1080/03670244.2012.719356#.VSST__mUeE4">scientific studies</a> examining the benefits of placentophagy, but it’s worth noting that out of the several thousand mammalian species, humans are among only a handful that don’t regularly consume the placenta.</p>
<p>Different cultures hold a <a href="http://catalogue.nla.gov.au/Search/Home?lookfor=isn%3A%229023233662%22">variety of beliefs</a> about the placenta. Indonesian and Malaysian cultures consider the placenta to be a sibling of the newborn, for instance. And, in China, it’s thought to be its first and finest clothing. They all have a deep reverence and appreciation for the placenta and its ceremonial role in the birthing event. </p>
<p>The placenta plays a critical role in pregnancy, foetal development and health throughout life. It may only be a temporary organ, but plays some of the most important roles in sustaining early life.</p><img src="https://counter.theconversation.com/content/28851/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Astrud Tuck receives funding from the Channel 7 Children's Research Foundation.</span></em></p>An incredibly complex and important organ in its own right, the placenta is only found in mammals. And how it functions has the potential to have profound effects on the lifelong health of the developing foetus.Astrud Tuck, Postdoctoral Research Fellow in Reproductive Health, University of AdelaideLicensed as Creative Commons – attribution, no derivatives.