Early Pregnancy Ondansetron Exposure is Associated with Increased Risk of Structural Birth Defects in Offspring in a Large, Us Population Sample


      To investigate the association between early pregnancy ondansetron use and risk of cardiac defects in a national level dataset.


      Maternal and child medical claims data were obtained from Truven Health Analytics for all live births from 2000 to 2014. Logistic regression was used to measure the association between early pregnancy exposure to ondansetron and risk of specific structural defects in offspring.


      Our dataset contained 1,149,145 live births from 1,004,175 mothers. Of these, 76,330 infants were exposed to ondansetron in-utero during the first trimester (5,557 exposed exclusively in medical settings), and 61,830 infants were diagnosed with structural defects. First trimester exposure to ondansetron in a medical setting was associated with increased risk of structural (OR: 1.34 95% CI: 1.23-1.47), cardiac (OR: 1.52 95% CI: 1.35-1.70) and orofacial cleft defects (OR: 1.32 95% CI: 0.76-2.28) in offspring compared to women with no antiemetic exposure during pregnancy. Risk was highly elevated for atrioventricular septal defects (OR: 2.68 95% CI: 1.61-4.47) and diaphragmatic hernia (OR: 2.49 95% CI: 1.18-5.25).


      This study in a large, US population demonstrates a statistically significant association between early pregnancy ondansetron and risk of structural birth defects in offspring. Our analysis addresses limitations of prior studies including limited power, exposure misclassification, and generalizability to the US population.