Researchers have identified a key genetic factor behind severe nausea and vomiting during pregnancy, a condition known as hyperemesis gravidarum, which affects up to 10.8% of pregnant individuals and can become so debilitating that it prevents eating, drinking and may require hospitalization.
The discovery comes from the largest genetic study conducted to date on the condition, published in April 2026. Scientists found that the gene responsible for producing the hormone “growth differentiation factor 15” (GDF15) is most strongly associated with hyperemesis gravidarum. This supports earlier hypotheses about the hormone’s potential role in triggering severe pregnancy-related nausea.
In addition to GDF15, researchers identified six other genes linked to the condition. One of these genes may influence the production of GLP-1, a hormone that regulates appetite and blood sugar levels and is likewise known to be a major genetic risk factor for type 2 diabetes.
The findings shift focus away from previously suspected causes such as human chorionic gonadotropin (hCG) or estrogen, which were thought to drive symptoms due to their elevated levels in early pregnancy. Instead, the study highlights fetal-derived GDF15 as a primary contributor, aligning with earlier research suggesting the fetus plays a direct role in maternal nausea.
Experts note that up to seven in ten pregnant individuals experience some form of nausea and vomiting, even as a smaller subset — estimated at one to three in every 100 pregnancies — develop severe symptoms classified as hyperemesis gravidarum. This condition remains one of the most common reasons for hospitalization during the first trimester.
Understanding the genetic and hormonal mechanisms behind severe pregnancy sickness could improve diagnosis, treatment, and support for those affected, offering hope for more targeted interventions in the future.
