Use of Nimesulide During Early Pregnancy and the Risk of Congenital Malformations: A Population-Based Study from Italy.

Introduction: Nimesulide is the most prescribed non-steroidal anti-inflammatory drug in Italy, and it is currently marketed in about 50 countries worldwide. The association between the use of nimesulide in early pregnancy and the risk of birth defects was investigated in a large cohort of pregnant women from Italy.
Methods: Data were from the healthcare utilization databases of the Italian region of Lombardy. The cohort of 353,081 newborns occurring in Lombardy during the period 2005-2010 was investigated. Exposure to nimesulide during the first trimester of pregnancy, and congenital malformations detected at presentation and within 90 days after birth (outcome), were investigated. Exposure-outcome association was measured by the ratio between the prevalence of congenital malformations among users and non-users of nimesulide. Propensity score stratification was used to control for potential confounders, including maternal medical comorbidities, concomitant medications and sociodemographic characteristics.
Results: The 627 (0.18%) women who filled prescriptions for nimesulide in the first trimester of pregnancy had a 2.6-fold risk of having children with congenital urinary tract anomalies compared to those who did not (adjusted prevalence ratio 2.6; 95% CI 1.2-5.7). Weaker and non-significant evidence for congenital malformations as a whole was found (adjusted prevalence ratio 1.2, 95% CI 0.9-1.6).
Conclusion: Our study suggests that the use of nimesulide in early pregnancy may result in a greater risk of having births with congenital urinary tract anomalies.
Funding: This study was funded by grants from the Italian Ministry of the Education, University and Research ('Fondo d'Ateneo per la Ricerca' portion, year 2015).