Science and Tech


Scientists discover cause of pregnancy morning sickness, test cures

Some 70% of women experience nausea and vomiting during pregnancy, and until now, an underlying cause was unknown.
Pregnant woman suffering from nausea sits at the end of her bed
Posted at 11:02 AM, Dec 14, 2023

In a breakthrough discovery, scientists have identified the cause of pregnancy morning sickness, raising hope for a possible cure.

Researchers found that a hormone exposed to pregnant women through the placenta — called GDF15 — is what triggers the nausea and vomiting, according to a study published in the journal Nature.

The study found that the severity of morning sickness a pregnant woman experiences is directly related to the amount of GDF15 she is exposed to. Until now, the underlying cause of nausea and vomiting in pregnancy had not been known.

"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," said Marlena Fejzo, a clinical assistant professor at the University of Southern California's Keck School of Medicine, and the study's author.

Women with typically lower levels of GDF15 become sicker when the hormone surges during pregnancy. But those already exposed to higher levels of the hormone are less affected. For example, women with beta-thalassemia, a condition where GDF15 levels are chronically high, report very low levels of nausea and vomiting during pregnancy.

Thus, decreasing levels of the hormone during pregnancy, or exposing women to it before pregnancy, could help ease morning sickness symptoms.

"Lowering GDF15 is one way to potentially address pregnancy sickness — and the present study provides the first human evidence that it is likely safe to do so," said the Keck School of Medicine of USC in a press release. "Another way to reduce symptoms involves exposing women to GDF15 prior to pregnancy, to 'prime' or prepare them for elevated levels of the hormone once they become pregnant."

Some 70% of women experience nausea and vomiting during pregnancy, including in its most severe form, known as hyperemesis gravidarum (HG), according to the study. HG is a persistent form of vomiting that can lead to a number of complications, including death in its most severe cases, according to the National Library of Medicine.

Scientists are moving forward with researching cures for morning sickness, including testing drugs that block GDF15 from binding to its receptor in the brain, and exposing women to the hormone prior to pregnancy.

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