Cambridge researchers discovered a single hormone produced by the fetus is the major cause of "morning sickness," the persistent, first-trimester nausea and vomiting that affects more than two-thirds of pregnant women. The breakthrough is expected to help prevent the condition as well as hyperemesis gravidarum—the severe form of the condition—which often leads to weight loss, dehydration, and miscarriage.
The GDF-15 protein, produced by various cells throughout the body, signals cellular stress and sends a message to the brain to reduce food intake. Researchers have known that GDF-15 prompts pregnancy nausea, but it wasn't clear whether the mother or the fetus was the source. The study tracked the increased GDF-15 to the placenta and fetus for the first time.
The research also showed a woman's previous exposure to the hormone determined her response during pregnancy. Participants with a type of blood disorder that elevated their GDF-15 levels had few symptoms, while women with prepregnancy deficiencies in the hormone typically had severe reactions. The findings are expected to lead to further clinical trials.