About 60,000 women are admitted to the hospital each year for extreme morning sickness. Morning sickness is a common symptom of pregnancy, but when cases get extreme women face dehydration and other serious side effects. Extreme morning sickness is clinically referred to as hyperemesis gravidarum (HG). In some cases, the morning sickness is so severe that voluntary abortion of the pregnancy is necessary to stop the nausea and vomiting.

Researchers at UCLA have found a possible link between family members suffering from extreme morning sickness. Women with HG were included in the study. Researchers traced family lines back on both maternal and fraternal sides to see if there were any other cases of HG along the bloodline and they found instances of potential genetic connection. If women are born into families with a history of HG the chance of having extreme morning sickness increases 17 times. The report was published on the Internet site for the American Journal of Obstetrics and Gynecology.

The study involved 650 women suffering from HG. These women were asked to bring in a friend or family member who had gone at least 27 weeks into a pregnancy without suffering from extreme morning sickness. In addition to the 17 fold increase in risk down the family blood line, 33% of women suffering from HG reported their mother had the same problem.

Authors concluded, “"Because the incidence of hyperemesis gravidarum is most commonly reported to be 0.5 percent in the population, and the sisters of cases have as much as an 18-fold increased familial risk for HG compared to controls, this study provides strong evidence for a genetic component to extreme nausea and vomiting in pregnancy.”

Source: Marlena Fejzo, Yafeng Zhang, Rita M. Cantor, Thomas M. Goodwin, Patrick Mullin, Kimber MacGibbon, Roberto Romero. American Journal of Obstetrics and Gynecology.  25 October, 2010.