Caffeine causes tiny muscles in the Fallopian tubes to slacken off, reducing their ability to help carry eggs from the ovary to the uterus, a U.S study has found.
Eggs must make the journey down the tubes if successful conception is to occur. Microscopic hairs called cilia are understood to help move the eggs along but the process is assisted by waves of muscle contractions in the Fallopian tubes.
In lab tests on mice, scientists from University of Nevada in the U.S found that caffeine reduced the muscle activity in the Fallopian tubes.
“This provides an intriguing explanation as to why women with high caffeine consumption often take longer to conceive than women who do not consume caffeine,” said Professor Sean Ward from the University of Nevada’s School of Medicine.
The study, which was published in the British Journal of Pharmacology, could also help doctors better understand pelvic inflammation, sexually-transmitted diseases and ectopic pregnancies, Professor Ward said.
Professor Robert Norman, an expert in reproductive medicine at the University of Adelaide, said that in this study, a lot of caffeine was needed to reduce fertility.
“The doses used were large and in vitro. The epidemiology around caffeine is weak but this may have some interest to fertility specialists as a potential mechanism for infertility,” he said.
However, he said women trying to conceive should consider cutting out coffee and caffeinated drinks.
“Most preconception lifestyle programs emphasise the reduction or elimination of caffeine so I think that is very sensible,” he said.