Objective: Tumor necrosis factor inhibitors (TNFi) are used by over 20% of pregnant women with chronic inflammatory diseases, which could further impede immune function and increase the risk of infections that require hospitalization. We assessed the risk of serious infections during pregnancy and postpartum between women exposed and unexposed to TNFi with chronic inflammatory diseases.
Methods: Using MarketScan, we identified pregnant women with chronic inflammatory diseases and modeled TNFi exposure during pregnancy and postpartum as a time-varying variable. Cox proportional hazards models estimated adjusted hazard ratios (HRs) for TNFi and the risk of hospitalized infection.
Results: We followed a total of 62,813 women who had 70,529 pregnancies and 69,412 births. Among these, 4,485 (7.1%) women were exposed to at least one TNFi prescription during pregnancy and 3,559 women during postpartum. Overall, 449 women were hospitalized for infection during pregnancy, including 31 pregnant women who were exposed to TNFi. During postpartum, 205 women had hospitalized infection, of which 17 women were TNFi-exposed. Compared with no TNFi exposure, TNFi treatment during pregnancy was associated with a HR of 1.39 (95% confidence interval [CI], 0.95-2.05) for serious infections, whereas the HR during postpartum was 1.22 (95% CI, 0.72-2.06).
Conclusion: In this population-based study, we found no statistically significant association between TNFi exposure during pregnancy and serious infection risk. Although point estimates were higher for pregnant women exposed to TNFi, CIs were wide and included the null, indicating that an increased risk cannot be ruled out. Given the frequency of TNFi treatment for pregnant women, these results support continued investigation and may inform counseling regarding TNFi treatment during pregnancy and postpartum.
© 2025 The Author(s). ACR Open Rheumatology published by Wiley Periodicals LLC on behalf of American College of Rheumatology.