Antiemetic Ondansetron During Pregnancy Does Not Harm Foetus

Ondansetron taken during pregnancy does not harm the foetus, affirms a recent study. Ondansetron is an antiemetic drug commonly prescribed to treat nausea and vomiting during pregnancy. Nausea and vomiting are common during pregnancy. While most cases do not warrant medications and can be managed conservatively, about 10 to 15% cases require consultation with a doctor. Nausea and vomiting that sets in between 3 and 8 weeks of gestation, and peaks by weeks 7 to 12 in most cases. Since it is during this period that the foetus is most susceptible to teratogenic effects i.e. effects that could result in malformations, the choice of drugs is to be made with great care. Ondansetron is one of the most frequently prescribed drugs to treat nausea and vomiting. This antiemetic drug works by antagonizing specific receptors called 5-hydroxytryptamine type 3 receptors.

Despite the widespread use, the safety of this drug for the fetus was not been well studied till recently. The drug was feared to be associated with an increased risk of cleft palate. The recent study funded by the Danish Medical Research Council analyzed a historical cohort of 608,385 pregnancies in Denmark. Women who were exposed to ondansetron and those who were not exposed were included.

Ondansetron was not found out to have any significant association with adverse outcomes such as spontaneous abortion, stillbirth, any major birth defect, preterm delivery, infants with a low birth weight or small-for-gestational-age size. The results were published in the Feb. 28 issue of the New England Journal of Medicine.

Many women are hesitant to resort to drugs like ondansetron to control severe nausea and vomiting during their first trimester of pregnancy. It is to be understood that severe dehydration and other adverse physiological effects caused by hyperemesis gravidarum (severe morning sickness) harm pregnancy if untreated. The results of the recent study affirm the safety of ondansetron in these cases.

Reference: Ondansetron in Pregnancy and Risk of Adverse Fetal Outcomes; Björn Pasternak et al; N Engl J Med 2013; 368:814-823

Source-Medindia