Boston—Nearly a fourth of expectant mothers use ondansetron, marketed as Zofran, to relieve nausea during pregnancy, according to a recent study, but research on how the medication affects fetal development is limited.
A report in JAMA notes that an estimated 22% of pregnant women in the United States had taken the drug at some point during their pregnancy in 2014. Ondansetron is a 5-HT3 receptor antagonist that is commonly prescribed for nausea and vomiting during pregnancy.
For the recent study, Brigham and Women’s Hospital researchers analyzed data from more than 88,000 pregnancies in which pregnant women had taken ondansetron during the first trimester to examine risk of cardiac malformations or oral clefts. Results suggest no heightened risk of cardiac malformations and a very small uptick in risk of oral clefts.
“Use of ondansetron has increased over time, but only a handful of studies had been conducted to date and all were relatively small. We wanted to provide more robust information on two important outcomes—risk of oral clefts and cardiac malformations—for patients and clinicians,” explained corresponding author Krista Huybrechts, MS, PhD, an epidemiologist in the Division of Pharmacoepidemiology and Pharmacoeconomics at the Brigham. “Our study expands the evidence available to date and represents the largest published study of tens of thousands of women and fetal outcomes with careful control for potential confounding variables.”
The retrospective cohort study was based on data from the nationwide Medicaid Analytic eXtract (MAX), a dataset that included more than 1.8 million pregnancies resulting in live births between 2000 and 2013 among publicly insured pregnant women. Prescriptions were filled for ondansetron in the first trimester for 88,467, 4.9%, of pregnancies during the study period.
Results indicate that 14,577 of about 1.7 million unexposed and 835 of 88,467 exposed infants were diagnosed with a cardiac malformation, for an absolute risk of 84.4 (95% CI, 83.0 to 85.7) and 94.4 (95% CI, 88.0 to 100.8) per 10,000 births respectively.
Absolute risk of oral clefts was 11.1 per 10,000 births (95% CI, 10.6 to 11.6) in unexposed infants versus 14.0 per 10,000 births in infants exposed to ondansetron in the first trimester.
“These results suggest that ondansetron does not meaningfully increase the risk of congenital malformations, although a small increase in the risk of oral clefts cannot be excluded,” Huybrechts pointed out. “These results will hopefully provide reassurance to pregnant women who experience nausea and vomiting in pregnancy and need to make a risk-benefit trade-off regarding treatment.”
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A report in JAMA notes that an estimated 22% of pregnant women in the United States had taken the drug at some point during their pregnancy in 2014. Ondansetron is a 5-HT3 receptor antagonist that is commonly prescribed for nausea and vomiting during pregnancy.
For the recent study, Brigham and Women’s Hospital researchers analyzed data from more than 88,000 pregnancies in which pregnant women had taken ondansetron during the first trimester to examine risk of cardiac malformations or oral clefts. Results suggest no heightened risk of cardiac malformations and a very small uptick in risk of oral clefts.
“Use of ondansetron has increased over time, but only a handful of studies had been conducted to date and all were relatively small. We wanted to provide more robust information on two important outcomes—risk of oral clefts and cardiac malformations—for patients and clinicians,” explained corresponding author Krista Huybrechts, MS, PhD, an epidemiologist in the Division of Pharmacoepidemiology and Pharmacoeconomics at the Brigham. “Our study expands the evidence available to date and represents the largest published study of tens of thousands of women and fetal outcomes with careful control for potential confounding variables.”
The retrospective cohort study was based on data from the nationwide Medicaid Analytic eXtract (MAX), a dataset that included more than 1.8 million pregnancies resulting in live births between 2000 and 2013 among publicly insured pregnant women. Prescriptions were filled for ondansetron in the first trimester for 88,467, 4.9%, of pregnancies during the study period.
Results indicate that 14,577 of about 1.7 million unexposed and 835 of 88,467 exposed infants were diagnosed with a cardiac malformation, for an absolute risk of 84.4 (95% CI, 83.0 to 85.7) and 94.4 (95% CI, 88.0 to 100.8) per 10,000 births respectively.
Absolute risk of oral clefts was 11.1 per 10,000 births (95% CI, 10.6 to 11.6) in unexposed infants versus 14.0 per 10,000 births in infants exposed to ondansetron in the first trimester.
“These results suggest that ondansetron does not meaningfully increase the risk of congenital malformations, although a small increase in the risk of oral clefts cannot be excluded,” Huybrechts pointed out. “These results will hopefully provide reassurance to pregnant women who experience nausea and vomiting in pregnancy and need to make a risk-benefit trade-off regarding treatment.”
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