Scientists pinpoint cause of severe morning sickness
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Researchers said the discovery could lead to better treatments for morning sickness, including rare and life-threatening cases of it.
PHOTO: UNSPLASH
NEW YORK - The nausea and vomiting that often define the first trimester of pregnancy are primarily caused by a single hormone, according to a study published on Dec 13 in the journal Nature.
Researchers said the discovery could lead to better treatments for morning sickness, including rare and life-threatening cases of it.
The study confirms prior research that had pointed to the hormone, called GDF15.
The researchers found that the amount of hormone circulating in a woman’s blood during pregnancy – as well as her exposure to it before pregnancy – drives the severity of her symptoms.
More than two-thirds of pregnant women experience nausea and vomiting during the first trimester.
And roughly 2 per cent of women are hospitalised for a condition called hyperemesis gravidarum, which causes relentless vomiting and nausea throughout the entire pregnancy.
Perhaps because nausea and vomiting are so common in pregnancy, doctors often overlook hyperemesis, dismissing its severe symptoms as psychological, even though it is the leading cause of hospitalisation during early pregnancy, experts said.
“I’ve been working on this for 20 years, and yet there are still reports of women dying from this and women being mistreated,” said Dr Marlena Fejzo, a geneticist at the University of Southern California Keck School of Medicine and a co-author of the new study.
Hormones are chemicals that send messages across the body.
GDF15 is released by many tissues in response to stress, such as an infection.
Its signal is highly specific: Receptors for the hormone are clustered in a part of the brain responsible for feeling sick and vomiting.
In the study, Dr Fejzo and collaborators at the University of Cambridge in England measured the hormone in pregnant women’s blood and analysed the genetic risk factors for hyperemesis.
The researchers found that women experiencing hyperemesis had significantly higher GDF15 levels during pregnancy than did those who had no symptoms.
But the hormone’s effect seems to depend on the woman’s sensitivity and exposure to the hormone before pregnancy.
The researchers found, for example, that women with a rare blood disorder causing chronically high levels of GDF15 rarely experienced nausea or vomiting in pregnancy.
In lab experiments, the scientists exposed some mice to a small amount of the hormone. When given a much larger dose three days later, the mice did not lose their appetites as much as did animals that were not given the earlier dose – showing a robust effect of desensitisation. NYTIMES
