We know nausea and vomiting is common all times of day during pregnancy. Calling it morning sickness contributes to the stigma and misunderstanding of the condition.
Hyperemesis gravidarum causes severe nausea and vomiting during pregnancy. Even though it affects up to 3 percent of pregnancies, research about its causes and treatments is sparse.
It can be hard to eat a balanced diet when you are suffering from nausea and vomiting. You may only feel like oranges, hot chips, lemonade, ice blocks and pizza.
Professor and Co-Director of the Institute of Metabolic Science and Director of the Medical Research Council Metabolic Diseases Unit, University of Cambridge