Pregnancy: Nausea in pregnant women can be caused by fetal hormones.

It’s a symptom that pregnant women would do just fine without and that affects seven out of ten pregnancies: nausea and vomiting. But a major discovery could pave the way for a treatment. According to a study published recently in the journal Nature involving scientists at the University of Cambridge and researchers from Scotland, the United States and Sri Lanka, these ailments are caused by a hormone produced by the fetus, a protein known as HDF15.

For some women (one to three in 100 pregnancies), these symptoms can be severe. This is called hyperemesis gravidarum and is the most common reason women are hospitalized during the first three months of pregnancy. Kate Middleton, Prince William’s wife, particularly suffered from this condition during her three pregnancies.

To arrive at their result, the researchers looked at data from women included in a number of studies and used a combination of approaches: measuring hormones in the blood of pregnant women, studies in cells and mice, etc. They showed that the degree of nausea and vomiting experienced women during pregnancy are directly related to both the amount of GDF15 produced by the fetal part of the placenta and sent into its bloodstream, and its sensitivity to the action of this hormone.

Genetic association

Notably, the team found that some women have a much higher genetic risk of hyperemesis gravidarum, associated with lower levels of the hormone in the blood and tissues outside of pregnancy. Similarly, women with the inherited blood disorder beta thalassemia, which allows them to have very high levels of GDF15 before pregnancy, experience little or no nausea and vomiting.

“A baby growing in the womb produces the hormone in quantities to which the mother is not accustomed. The more sensitive she is to this hormone, the worse she will be,” summed up Professor Stephen O’Rahilly, co-director of the Wellcome-Medical Research Council Institute of Metabolic Sciences at the University of Cambridge, one of the study’s authors. . “Knowing this gives us a clue as to how we can prevent it,” he continued.

Co-author Dr. Marlena Feizo of the University of Southern California, whose team previously identified a genetic link between GDF15 and hyperemesis gravidarum, suffered from the disease herself: “When I was pregnant, I could barely walk without getting sick,” she said. . “I hope that now that we understand the cause, we are closer to developing effective treatments.”