Fetuses make a protein that causes morning sickness in pregnancy

Desensitizing people to the protein before pregnancy or blocking its action may help

A woman with long dark hair wearing a white T-shirt holds her right hand over her mouth while her left hand braces her against the wall. The image conveys nauseousness.

Nausea and vomiting are common during pregnancy. Researchers have found a major driver of the illness, which can sometimes be severe enough to require hospitalization.

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A surge of a hormone made by fetuses triggers the stomach-turning nausea and vomiting of morning sickness, a new study suggests.

People who have naturally low levels of the protein in their blood before pregnancy are more susceptible to a severe form of morning sickness called hyperemesis gravidarum when hit with the rush of protein, researchers report December 13 in Nature.