Q# 16-08: Ondansetron and Fetal Abnormality
This project aims to investigate the association between use of ondansetron in pregnancy and the risk of fetal abnormalities. We identified 50,269 pregnancies with antiemetic medications exposure during pregnancy: 54 pregnancies exposed to ondansetron, 49,885 pregnancies exposed to pyridoxine/doxylamine, and 1,735 pregnancies exposed to metoclopramide. Results indicated increased risk of major congenital malformation comparing pregnancies exposed to antiemetic medications during the 1st trimester to the unexposed group (adjusted odds ratio – aOR: 1.07; 95%CI: 1.03-1.11). When the antiemetic medications were analysed separately, we found higher risk associated with pyridoxine/doxylamine (aOR: 1.07; 95%CI: 1.03-1.11) and metoclopramide (aOR: 1.27; 95%CI: 1.03-1.57); the risk for pregnancies exposed to ondansetron was lower (aOR: 0.57), but the result was not statistically significant (95%CI: (0.13-2.49). Similar trends were observed for exposure at any point during the pregnancy. Full results of this analysis were presented in a separated report submitted in June 2017. A manuscript of the results is being revised in preparation for submission to JAMA at the end of August.