pregnancy nausea vomiting

Researchers from Denmark recently published a study into the drug Ondansetron, typically prescribed for pregnancy nausea and vomiting. The study used data collected by Denmark registries to review more than 600,000 singleton births. The results of the study were published in the New England Journal of Medicine.

Some pregnancy nausea and vomiting is to be expected during a normal pregnancy, but prolonged or severe cases are often treated with antiemetic or anti-nausea and vomiting, drugs. Ondansetron is one such drug. Using Denmark registries, researchers were able to track prescriptions filled by pregnant women and compare women who filled prescriptions for the drug against control peers.

About 1,900 women filled a prescription for Ondansetron during pregnancy. Four controls were selected for each active group member. About 50% of the women prescribed the antiemetic were hospitalized for vomiting and nausea. Fifty percent of the women also used another antiemetic.

When researchers compared singleton birth results in the active group to the control group no differences in pregnancy, birth or fetal risk was noted. The rate of spontaneous abortion in the active group was about 1.1%. That number was significantly lower than the control group with a reported 3.7% spontaneous abortion rate in the first 12 weeks. The number of spontaneous abortions dropped slightly in the active group between weeks 13 and 22 to 1% and significantly in the control group to 2%. Rates of stillbirth were also lower in the active group. Researchers also noted cases of major birth defect, preterm deliveries, and low birth weight. While numbers were higher in the Ondansetron group, the difference was not statistically significant. 

Researchers noted that cofounders may play a role in clinical outcome and risk of adverse side effects, but as the study stands, Ondansetron does not appear to increase the risk of adverse side effects when taken during pregnancy.

Source: Bjorn Pasternak, MD, PhD, Henrik Svanstrom, MSc, Anders Hviid, Dr Med Sci. N Engl J Med 2013. 368:814-823. February 28, 2013. DOI: 10.1056/NEJMoa1211035.