Researchers Finally Have Answers About What Causes Severe Morning Sickness

This means there's potential for a cure down the road.
ByAnisa Arsenault
Associate Editor
March 22, 2018
pregnant woman on her bed with severe morning sickness
Image: iStock

There’s your run-of-the-mill morning sickness during pregnancy, and then there’s hyperemesis gravidarum. The latter—an extreme, persistent nausea and vomiting—is rare, affecting only about 2 percent of pregnancies. And it’s severe: It can lead to weight loss and land you in the hospital with dehydration. Anyone who has experienced hyperemesis gravidarum (like Kate Middleton) knows it’s the real deal, and two new studies are working to pinpoint the cause in order to emphasize it’s a physical, not a psychological, condition.

The culprit seems to be the excess of a blood-borne protein, growth differentiation factor 15 (GDF15). For University of California geneticist Marlena Fejzo, making this discovery was a cause especially close to her heart; she lost a baby because of complications from hyperemesis gravidarum in 1999. Fejzo, who initially researched cancer genetics, hypothesized genes could play a role in morning sickness as well. To get a wide sampling of of women’s experiences, she persuaded genetic testing company 23andMe to incorporate questions about pregnancy sickness into its surveys.

Ultimately, Fejzo and her team were able to compare the genomes of 1,306 women who said they received IVs for their nausea and vomiting during pregnancy to the genomes of 15,756 pregnant women who didn’t experience nausea or vomiting. The most significant difference between the two groups? The first had the gene for GDF15.

In a second, unrelated study, Stephen O’Rahilly of the University of Cambridge found that women who reported vomiting during their second trimester had more GDF15 in their blood at 12 to 18 weeks than those who didn’t.

So can we use this information to cure severe morning sickness? Eventually, researchers hope. But while scientists have knocked out GDF15’s receptor in the brains of mice, it’s too soon to consider testing the same strategy in pregnant women.

H/T Science Magazine

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