August 9, 2017

Ondansetron and fetal abnormality

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 in June 2017.

A manuscript of the results is under review by the Journal of Clinical Epidemiology. Our results suggested that doxylaminepyridoxine and metoclopramide use were associated with an increased risk of overall major congenital malformations (MCM). Doxylaminepyridoxine exposure was also associated with increased risks of spina bifida, nervous system and musculoskeletal system defects. Metoclopramide exposure was associated with an increased risk of genital organ defects. No significant association was found between ondansetron exposure and the risk of overall MCM. Nevertheless, caution is warranted given the few exposed pregnancies and thus the lack of statistical power. Our data may be used to guide clinicians in making an informed decision in the treatment of NVP during pregnancy.

For more information contact: Jessica (Lifang) Wang. Research Coordinator. [email protected]   514.934.1934 ext.44718