Nausea Medicine Okay for Expecting Moms

Ondanestron taken during pregnancy does not increase risks to unborn baby

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) Some women take medication for severe morning sickness. But it is sometimes difficult to gather enough information to know if medicines are always safe enough for unborn babies.

A recent study found that one nausea medication did not appear to increase the risk of negative pregnancy outcomes.

The medication called ondansetron (brand name Zofran) is often prescribed to pregnant women for nausea or vomiting.

Women who took this medicine during pregnancy were not more likely to have a miscarriage, stillbirth or preemie.

They were also not more likely to have a baby with a birth defect or a baby born underweight or with a low birth weight.

"Attend all prenatal appointments."

The study, led by Björn Pasternak, MD, PhD, of the Department of Epidemiology Research at Statens Serum Institut in Copenhagen, Denmark, looked at the possible risks to unborn babies caused by the drug ondansetron.

The researchers used data from 608,385 pregnancies in Denmark during the period of January 1, 2004 through March 31, 2011.

For each pregnant woman included in the study who had taken ondansetron, the researchers included four pregnant women of similar demographics who did not use ondansetron for comparison.

The researchers specifically looked at six different outcomes: miscarriage, stillbirth, major birth defects, preterm birth, low birth weight and babies born underweight (small for the pregnancy week when they were born).

The researchers did not find that taking ondansetron increased the risk for any of these outcomes.

Miscarriages between the 7th and 12th weeks of pregnancy occurred in 1.1 percent of the women who took ondansetron and 3.7 percent of the women who did not take it.

Miscarriages between the 13th and 22nd weeks of pregnancy occurred in 1 percent of the women who took ondansetron and 2.1 percent of the women who did not.

The rates of stillbirth were nearly identical across both groups: 0.3 percent of women taking ondansetron and 0.4 percent of women not taking it had stillbirths.

Similarly, 2.9 percent of the women in each group gave birth to a child with a major birth defect.

A total of 6.2 percent of the women taking ondansetron and 5.2 percent of the women who did not take it had a preterm delivery - giving birth before the 37th week of pregnancy.

Rates for low-birth weight babies and underweight (small for gestational age) babies were also similar across both groups. While 4.1 percent of women taking ondansetron had babies with a low birth weight, 3.7 percent of women not taking it had low birth weight babies.

About a tenth (10.4 percent) of women who took ondansetron had babies who were small for their pregnancy-week age, and 9.2 percent of women who did not take the medication had babies who were  small for their gestational age.

The researchers concluded that "ondansetron taken during pregnancy was not associated with a significantly increased risk of adverse fetal outcomes."

The study was published February 27 in the New England Journal of Medicine. The research was funded by the Danish Medical Research Council.

Reviewed by: 
Review Date: 
February 27, 2013
Last Updated:
February 27, 2013