Ondansetron taken during pregnancy does not increase risk of adverse fetal outcomes

Danish researchers find women who take ondansetron during pregnancy to treat nausea and vomiting does not increase the risk of adverse fetal outcomes, according to study results published in the Feb. 28 issue of the New England Journal of Medicine.

A historical cohort study of 608,385 pregnant women in Denmark included both those who took ondansetron and those who didn’t in a 1:4 ratio, in an analyses of the following adverse outcomes: spontaneous abortion (1,849 exposed women vs. 7,396 unexposed women), stillbirth (1,915 vs. 7,660), any major birth defect (1,233 vs. 4,932), preterm delivery (1,792 vs. 7,168), and birth of infants at low birth weight and small for gestational age (1,784 vs. 7,136).

Ondansetron was not associated with a significantly increased risk in spontaneous abortion (1.1% of exposed women vs. 3.7% of unexposed women during gestational weeks 7 to 12 and 1% vs. 2.1%, respectively, during weeks 13 to 22), stillbirth (0.3% for exposed women vs. 0.4% for unexposed women), any major birth defect (2.9% vs. 2.9%), preterm delivery (6.2% vs. 5.2%), delivery of low-birth-weight baby (4.1% vs. 3.7%), delivery of a small-for-gestational-age baby (10.4% vs. 9.2%).

The research was funded by the Danish Medical Research Council.