Study shows extreme form of pregnancy-related morning sickness could be genetic

November 4, 2010 By Enrique Rivero, University of California Los Angeles

(PhysOrg.com) -- Approximately 60,000 pregnant women are hospitalized each year due to hyperemesis gravidarum (HG), an extreme form of nausea and vomiting that endangers their lives and often forces them to reluctantly terminate their pregnancies. 

And for women with sisters, mothers and grandmothers on either side of the family who have experienced extreme morning sickness during pregnancy, the risk of HG may be heightened, according to a new study led by researchers from UCLA and the University of Southern California.

Researchers traced both the maternal and paternal family histories of women with HG and found not only that the condition could be genetic but that women with sisters who had HG could have a more than 17-fold risk of experiencing the debilitating condition too.

The findings are published online in the .

" with a family history of extreme nausea in pregnancy should be aware that they may have it too, and health care providers should take a family history of nausea in pregnancy at the first visit with an obstetrician," said lead author Marlena Fejzo, an assistant professor of hematology–oncology at the David Geffen School of Medicine at UCLA and an assistant professor of maternal and fetal medicine at Keck School of Medicine of USC. "The high familial prevalence strongly suggests a genetic component to this condition."

Researchers surveyed about 650 participants for the joint study on the genetics and epidemiology of HG. Women who had been diagnosed with HG and treated with IV fluids were asked to recruit, as a control, a friend who had at least two pregnancies lasting more than 27 weeks and who had not had HG. The researchers then compared the family histories of extreme nausea in the women with HG with those of the controls. Of the 650 participants, 207 women with HG and 110 controls had at least one sister who had been pregnant.

The researchers found that women with HG were more than five times as likely as the controls to report having a sister with severe morning sickness or HG. When including sisters who had experienced HG — and excluding sisters with just severe — study participants with HG had 17.3 times the odds of also having the condition. In addition, 33 percent of the women with HG reported having an affected mother, compared with only 8 percent of the controls.

Among the  who had information regarding their grandmothers' pregnancies, 18 percent of those with HG had a maternal grandmother with HG, and 23 percent had a paternal grandmother affected by the condition, suggesting that it can be passed on through the women's fathers.

The authors noted that their findings could be limited by factors such as having used the Internet to survey the participants and the fact that the family histories were based on self-reports, which can lead to misclassification.

"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," the authors conclude.

Previous studies have used hospitalization, clinical and other records to examine the prevalence of this mysterious condition among various population sets. One looked at medication in identical twins, compared with fraternal twins, and another focused on mother-to-daughter recurrence. Overall, the prior studies also suggested that genetics are involved.

Related Stories

Recommended for you

Discovery of the 'pioneer' that opens the genome

January 23, 2018
Our genome contains all the information necessary to form a complete human being. This information, encoded in the genome's DNA, stretches over one to two metres long but still manages to squeeze into a cell about 100 times ...

Researchers identify gene responsible for mesenchymal stem cells' stem-ness'

January 22, 2018
Many doctors, researchers and patients are eager to take advantage of the promise of stem cell therapies to heal damaged tissues and replace dysfunctional cells. Hundreds of ongoing clinical trials are currently delivering ...

Genes contribute to biological motion perception and its covariation with autistic traits

January 22, 2018
Humans can readily perceive and recognize the movements of a living creature, based solely on a few point-lights tracking the motion of the major joints. Such exquisite sensitivity to biological motion (BM) signals is essential ...

Peers' genes may help friends stay in school, new study finds

January 18, 2018
While there's scientific evidence to suggest that your genes have something to do with how far you'll go in school, new research by a team from Stanford and elsewhere says the DNA of your classmates also plays a role.

Two new breast cancer genes emerge from Lynch syndrome gene study

January 18, 2018
Researchers at Columbia University Irving Medical Center and NewYork-Presbyterian have identified two new breast cancer genes. Having one of the genes—MSH6 and PMS2—approximately doubles a woman's risk of developing breast ...

A centuries-old math equation used to solve a modern-day genetics challenge

January 18, 2018
Researchers developed a new mathematical tool to validate and improve methods used by medical professionals to interpret results from clinical genetic tests. The work was published this month in Genetics in Medicine.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.