OBJECTIVE:

To determine whether ondansetron exposure in the first trimester is associated with an increased risk of any congenital malformations. As secondary outcomes, determine if it is associated with a higher overall risk of congenital heart disease, interventricular septal defects, orofacial malformations, cleft lip defect (with or without palate) or cleft palate.

METHODOLOGY:

A systematic review with meta-analysis was carried out. The search was carried out in the following databases: PUBMED, EMBASE and LILACS, randomized studies, cohorts and cases and controls were chosen.

RESULTS:

15 studies were included, 11 cohort studies and four case-control studies, with 245,679 women exposed to ondansetron in the first trimester. No statistically significant association was found with overall congenital malformations (OR, 1.1; 95%, CI 0.99-1.22 I2: 72%), nor with congenital heart diseases (OR, 1.05; 95%, CI 0.95-1.19 I2: 78%) not with ventricular septal defects (OR, 1.2 95% CI 0.97 - 1.45 I2: 85%). A small increased risk was found for overall orofacial defects (OR, 1.17 95% CI 1.04 - 1.32 I2:0%), no increased risk was found for lip defect (with or without palate) (OR, 1.01 CI 95% 0.84 -1.21 I2%: 0%) or cleft palate (OR, 1.16 95% CI 0.9 - 1.5 I2: 31%).

CONCLUSION:

The results show that the use of ondansetron in the first trimester is not associated with an increase in overall congenital malformations, nor with an increase in heart disease, cleft lip and/or palate, but there is a slight increase in the risk of orofacial malformations.