Racial differences in risk of spontaneous abortions associated with periconceptional over-the-counter nonsteroidal anti-inflammatory drug exposure

Purpose: Nonsteroidal anti-inflammatory drugs (NSAIDs) are one of the most common medications reported in pregnancy. NSAIDs directly impact prostaglandin pathways and have been proposed as potential risk factors for spontaneous abortions (SABs, gestation <20 weeks). SAB risk and drug response across several medications differ by race; therefore, we evaluated whether associations between NSAIDs and SAB risk differ by race. Methods: Women were enrolled in the Right from the Start (2004-2010) prospective cohort. Data regarding over-the-counter NSAIDs up to the sixth week of pregnancy were obtained from interviews. Race was self-reported. Cox proportional hazards regression models were used to estimate the association between NSAID exposure and SAB, adjusted for confounders. Results: Among 2493 pregnancies, 12% were African American and 88% were Caucasian. NSAID exposure was reported by 40% (n = 124) of African Americans and 43% (n = 945) of Caucasians. Race-stratified analyses showed protection from SAB among African Americans (adjusted hazard ratio [aHR], 0.84; 95% confidence interval [CI], 0.73-0.96) but no effect in Caucasians (aHR, 1.01; 95% CI 0.88-1.16). Conclusions: Our findings suggest that risk for SAB due to over-the-counter NSAIDs in early pregnancy is modified by race. Further investigation of dose, timing in gestation, and indication may help to further reconcile the relationship between race, NSAIDs, and SAB.