Taking the anti-nausea drug ondansetron (Zofran) during pregnancy does not seem to increase the risk of major malformations in the baby, according to a new report.

Ondansetron is approved for the treatment of nausea and vomiting caused by chemotherapy. However, in recent years the drug has been given as a “last resort” to women who experience severe nausea and vomiting during pregnancy, explain the authors of a report in the medical journal BJOG: an International Journal of Obstetrics and Gynecology.

However, little is known about the safety of ondansetron when it’s used during pregnancy.

To investigate, Dr. Adrienne Einarson, from The Hospital for Sick Children in Toronto, and colleagues assessed the rate of major malformations among pregnant women exposed to ondansetron, other anti-emetic medications, or drugs that are known not to cause birth defects.

Each group included 176 women who had called a pregnancy help line in Canada or Australia.

Among the women treated with ondansetron there were a total of 169 live births, 5 miscarriages, 2 therapeutic abortions, and 6 babies born with major malformations. The average birthweight was 3362 grams.

These figures were not significantly different in the other groups.

“To our knowledge, this is the first study that examined the use of ondansetron in terms of safety during pregnancy,” the investigators note.

Although the results suggest that ondansetron can be safely used during pregnancy, larger studies are needed to a reach a definite conclusion, they add.

SOURCE: BJOG, September 2004.