Biologic use during pregnancy in patients with autoimmune conditions and pre-conception biologic use: a retrospective study comparing utilization during and after pregnancy across different autoimmune conditions

Objective: To examine the utilization of biologics during pregnancy and 6 months thereafter among patients with pre-conception biologic use. Design: This is a retrospective cohort study Population or sample: Pregnant individuals with an autoimmune condition and prior biologic use. Methods: We used Merative® MarketScan® Research Databases to identify pregnancies with one of the following conditions: inflammatory bowel disease (IBD), rheumatoid arthritis (RA), psoriatic arthritis (PsA), multiple sclerosis (MS), ankylosing spondylitis (AS), systemic lupus erythematosus (SLE), or Juvenile Idiopathic Arthritis (JIA). Pregnancies were included if they had used a biologic 6 months before conception. Main Outcome Measures: Proportion of pregnancies with biologic use at each pregnancy trimester, association between biologic discontinuation and individual AID. Results: Our study included 3,026 pregnancies. Overall, biologic utilization declined during pregnancy, with 65.2%, 52.5%, and 50.7% in the first, second, and third trimester respectively. Maternal age- and conception year-adjusted odds ratios for discontinuation in pregnancies with live deliveries was 12.9 (95% CI=6.3-26.3) for SLE, and 7.5 (95% CI = 5.56 – 10.14) for PsA when compared to IBD. A higher proportion of live deliveries were observed in pregnancies with IBD who continued biologic use (70.9% vs 51.7%) while persons with PsA (63.37% vs 68.1%), AS (60.0% vs 67.4%), and SLE (42.9% vs 71.9%) had lower proportion of live births. Conclusion: Biologic utilization declined during pregnancy in patients with AID and pre-conception biologic use with notable variations in discontinuation and pregnancy outcomes observed among AID conditions. Studies evaluating the risks and benefits of biologics specific to autoimmune diseases during pregnancy are warranted.