Increased Biologic Uptake in Pregnant Albertan Women with Rheumatoid Arthritis (RA), Spondyloarthritis (SpA) and Psoriatic Arthritis (PsA) Not Associated with Worse Peripartum Outcomes

Objectives Albertan women without immune-mediated inflammatory diseases (IMID) have better peripartum outcomes than those with RA, SpA and PsA.[1] Rheumatologists increasingly use peripartum biologics; however, concerns regarding their safety remain. We examined medication use and maternal/neonatal outcomes in a contemporary population-level, pregnancy birth cohort including those with RA, SpA, and PsA. Methods Study population included all singleton pregnancies with ≥22 weeks of gestation, July 2008 and December 2024 in Alberta, Canada. Previously validated algorithms based on ICD-10 codes identified women with RA, SpA, PsA and no IMID.[1] We compared maternal characteristics, comorbidities and neonatal outcomes between no IMID and RA/PsA/SpA groups. Dispensation of RA/SpA/PsA medications during pregnancy was evaluated in 2 time periods (2008-2016; 2017-2024). Proportion of days covered (PDC) during pregnancy for each medication was calculated to estimate adherence. In the RA and SpA/PsA groups, logistic regression calculated the odds of delivering preterm and small-for-gestational-age (SGA) infants when exposed to biologics after adjusting for maternal factors. Results Among 788,996 pregnancies of 474,197 women, 1627 pregnancies were by women with RA, 1017 with SpA/PsA and 786,352 with no IMID. Among live births, RA pregnancies had higher rates of SGA babies (RA 13%, SpA/PsA 8%, no IMID 10%). RA and SpA/PsA pregnancies had more NICU admissions than without IMID (RA 13%, SpA/PsA 12%, no IMID 10%). Prescription dispensations for RA and SpA/PsA between 2008-2016 and 2017-2024 did not change for corticosteroids (RA 19% to 18%, SpA/PsA 12%), increased in RA for antimalarials (24% to 34%), and pregnancy safe DMARDs (11% to 15%). Biologic uptake and associated mean PDC (SD) increased from 12% (32 (29)) to 23% (58 (33)) in RA and 9% (31(32)) to 26% (71 (31)) in SpA/PsA. In multivariable models, no/low/medium PDC compared to high PDC biologic use was not associated with higher risk of delivering preterm or SGA infants in RA, SpA, and PsA (Table 1). Factors associated with preterm labor in RA women included “Not married” status, preeclampsia and in SpA/PsA - gestational hypertension and pre-eclampsia. Factors associated with SGA included maternal age > 35 years, material deprivation, multiparity, and preclampsia for RA; and multiparity for SpA/PsA. Table 1. Associations between preterm and small for gestational age deliveries for Albertan women with RA, SpA/PsA* and level of adherence to biologics, and maternal characteristics Conclusion Biologic use in the peripartum period has increased in women with RA, SpA, and PsA without negative impacts on preterm labor and SGA. Factors such as pre-eclampsia play a large role in worse peripartum outcomes. Understanding adherence to pregnancy safe medications throughout pregnancy is needed. References [1.] Keeling S. J Rheumatol 2020;47:197-203. Supported by a CIORA grant