Severe Morning Sickness May Be Heriditary


Women whose sisters experienced extreme morning sickness during pregnancy are 17 times more likely to develop the condition during their own pregnancies, suggests a new study.

Researchers from UCLA and the University of Southern California looked at patterns of morning sickness in 650 related mothers and concluded that extreme morning sickness — known as hyperemesis gravidarum (HG) — may actually be hereditary.

“Pregnant women with a family history of extreme nausea in pregnancy should be aware that they may have it too,” said lead author Marlena Fejzo of UCLA, “and health care providers should take a family history of nausea in pregnancy at the first visit with an obstetrician.”

Did your sister get admitted to the hospital for morning sickness-related dehydration? Did you? Did your mother?

HG is the kind of morning sickness that can be totally debilitating and even life-threatening. In fact, it has led some women to terminate their pregnancies. There’s intense throwing up, constant nausea and often some period of hospitalization in order to get crucial fluids and nutrients into mom’s system. It’s not as common as morning sickness which affects most pregnant women to some degree. HG is thought to affect about 1% of pregnant women.

The study found that sisters of women who had experienced HG were 17.3 times more likely to have the condition than sisters of women who had little to no morning sickness. Also, about a third of the women with HG reported that their mothers also suffered. “The high familial prevalence strongly suggests a genetic component to this condition,” Fejzo said.

The findings were published in the American Journal of Obstetrics and Gynaecology this month.