Scientists have finally figured out why many women experience morning sickness in the first trimester of pregnancy. In a study published in the journal Nature on Wednesday, researchers revealed that the nausea and vomiting many experience in the first trimester — and that others suffer throughout their entire pregnancies — is largely caused by one hormone, GDF15. The findings could help lead to more effective treatments for morning sickness, which can be so severe and debilitating for some women that they require hospitalization.
“We now know that women get sick during pregnancy when they are exposed to higher levels of the hormone GDF15 than they are used to,” Marlena Fejzo, a professor at University of Southern California’s Keck School of Medicine who worked on the paper, told the Guardian. For pregnant individuals, their GDF15 level tends to skyrocket because the fetus produces the hormone, which results in nausea and vomiting.
According to the New York Times, more than 70 percent of pregnant women suffer from nausea during the first trimester. About 2 percent of women are hospitalized for hyperemesis gravidarum, a condition defined by severe vomiting that can lead to malnutrition, weight loss, and dehydration. It also can increase the risk of blood clots, a baby being born early, and preeclampsia, which can threaten the lives of the mother and child. “I’ve been working on this for 20 years and yet there are still reports of women dying from this and women being mistreated,” Fejzo told the Times.
Sir Stephen O’Rahilly, a co-director of the Wellcome-Medical Research Council Institute of Metabolic Science at the University of Cambridge who led the international collaboration behind the discovery, told the Guardian that knowing that the more sensitive a mother is to GDF15, the sicker she will become during her pregnancy could help researchers discover more treatments or a cure for morning sickness. “Knowing this gives us a clue as to how we might prevent this from happening,” he said.