Study: No link between birth defects, anti-nausea drug

Despite previous studies and nearly 200 lawsuits, a researcher at UCLA said morning sickness is more likely to blame for defects than the drug Zofran.

By Stephen Feller

LOS ANGELES, May 9 (UPI) -- Women treated with a drug for nausea during pregnancy are not increasing the risk for birth defects, a new study shows, rebutting others suggesting the drug could be dangerous to the fetus.

The new study, conducted at the University of California Los Angeles, suggests women with extreme morning sickness are at greater risk for birth defects regardless of treatment for nausea.


The drug ondansetron, sold as Zofran, is frequently prescribed to women with Hyperemesis Gravidarum, a form of extreme morning sickness that can cause continuous nausea and vomiting so violent is has caused eardrums to blow and ribs to crack. The condition sometimes requires intravenous fluids and feeding tubes, and even hospitalization.

Nearly 200 lawsuits have been filed against GlaxoSmithKline, which manufactures Zofran, for a range of birth defects from cleft palate to heart defects.

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Marlena Fejzo, an associate researcher at the David Geffen School of Medicine at UCLA, said that while women need to weigh the risk of exposing their fetus to the drug, her study suggests it may be less of a choice than the lawsuits have made it appear.


"What was really significant to me was that women with extreme morning sickness who took Zofran reported fewer miscarriages and terminations and experienced higher live birth rates," Fejzo said in a press release. "Taking this medication helped them get through their pregnancies and gave them their desired outcome, a live birth."

For the study, published in the journal of Reproductive Toxicology, the researcher analyzed data on 1,070 pregnancies of women who had morning sickness and used Zofran, comparing them to 771 pregnant women with morning sickness who did not use the drug and 1,555 women who did not have morning sickness and also did not use the drug.

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Overall, 5 out of 952 infants whose mothers had morning sickness and used Zofran were born with heart defects, compared to 8 of 1,286 infants whose mothers did not have morning sickness or use the drug. Among women who had morning sickness and used the drug, 1 out of 952 infants were born with cleft palate, compared to 2 out of 1,286 infants the comparison group.

Fejzo also reports women with a history of morning sickness who used Zofran had lower reports of miscarriage and termination, and a higher number of live births, than women who did not take the drug.


"This is the first study describing fetal outcome for more than 1,000 exposures to Zofran in the United States," said Fejzo. "I believe this data is critical to guide future decision-making regarding prescribing what is one of the most effective and most commonly prescribed off-label treatments for nausea and vomiting. The overall results do not support an increased risk of birth defects."

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