Use of disease-modifying antirheumatic drugs during pregnancy and risk of preeclampsia

Abstract

Objective: To describe patterns of disease-modifying antirheumatic drug (DMARD) use during pregnancy in a population-based cohort, and to evaluate the association between autoimmune disease, DMARDs, corticosteroids, and nonsteroidal antiinflammatory drugs (NSAIDs) and preeclampsia.

Methods: Using health care utilization databases from British Columbia (1997-2006), we compared the risk for preeclampsia among 44,786 women with and without autoimmune disease with study drug dispensings before pregnancy (past users) and before and during the first 20 gestational weeks (continuous users). Relative risks (RRs) and 95% confidence intervals (95% CIs) were estimated.

Results: Only 414 women (0.1%) had a DMARD dispensing during pregnancy. The incidence of preeclampsia was 2.3% for past DMARD users, 2.7% for past corticosteroid users, and 2.9% for past NSAID users. Compared to past users, the continuous DMARD user RR was 2.29 (95% CI 0.81-6.44), and was 0.89 (95% CI 0.51-1.56) for corticosteroid and 0.84 (95% CI 0.63-1.10) for NSAID users. Compared to women without autoimmune disease, the delivery year-adjusted RR was 2.02 (95% CI 1.11-3.64) for women with systemic lupus erythematosus (SLE). The DMARD results were attenuated when antimalarials were excluded, and the delivery year-adjusted RR was 0.95 (95% CI 0.25-3.55) when the DMARD analysis was restricted to women with autoimmune disease.

Conclusion: Few women were exposed to DMARDs during pregnancy. We observed a 2-fold increased risk of preeclampsia among women with SLE and a nonsignificant increase in risk in DMARD users. The DMARD and preeclampsia association was attenuated when antimalarials were excluded and null when restricted to women with autoimmune disease, which suggests the association is likely due to greater autoimmune disease severity in DMARD users.

Figure 1

Study timeline. LMP, last menstrual period.

Figure 2

Pre-pregnancy and pregnancy DMARD use among 306,831 pregnancies identified from the British Columbia healthcare utilization databases between 1997–2006. LMP, last menstrual period; DMARD, Disease-Modifying Antirheumatic Drug.