Scientists Pinpoint Culprit in Pregnancy Sickness

Scientists have their most solid lead yet on what drives the most severe form of morning sickness. A sweeping analysis of nearly 11,000 people with hyperemesis gravidarum (HG)—the debilitating nausea and vomiting that can land pregnant patients in the hospital—points to one hormone gene as the main player: GDF15. The study, published in Nature Genetics, found 10 genes tied to higher HG risk, with GDF15 emerging as the strongest signal across multiple ancestral groups.

The work backs up earlier, smaller studies and challenges long-standing theories that pinned HG on pregnancy hormones like hCG or estrogen. One newly implicated gene, TCF7L2, is already known as the top genetic risk factor for type 2 and gestational diabetes and may influence GLP-1, the hormone mimicked by drugs like Ozempic. Researchers say the findings could open doors to targeted treatments and better prediction of who's at risk. A clinical trial set to launch this summer will test whether the diabetes drug metformin, which raises GDF15 levels, can "desensitize" women with a history of HG before a future pregnancy and blunt symptoms the next time around.