The Impact of Medication Adherence on Peripartum Outcomes in Women with SLE: A Population-Level Analysis

Objectives Pregnancy outcomes of women with SLE are worse compared to those without immune-mediated inflammatory diseases (IMID). Factors contributing to higher risk may include concomitant corticosteroid or other medication use and active disease in the peripartum period. Despite international recommendations, the uptake of SLE treatments such as antimalarials during pregnancy remain suboptimal. We examined medication use and maternal/neonatal outcomes in a contemporary, population-level, pregnancy-birth cohort.

Methods The study population included all singleton pregnancies with ≥22 weeks of gestation, between July 2008 and December 2024 in Alberta, Canada. Previously validated algorithms based on ICD-10 codes were used to identify women with SLE and no IMID. We compared maternal characteristics, comorbidities and neonatal outcomes between no IMID and SLE groups. Dispensation of SLE-related medications 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. Logistic regression was used to calculate the odds of developing preterm labor when exposed to SLE-related medications after adjusting for maternal factors.

Results Among 787,346 pregnancies of 474,197 women, 994 pregnancies were by women with SLE and 786,352 had no IMID. Pregnant women with SLE were more likely to have renal disease (No IMID 5% vs SLE 10.4%), pre-existing hypertension (No IMID 7.6% vs SLE 23.5%), pre-eclampsia/eclampsia (No IMID 4% vs SLE 9.9%) while neonates in mothers with SLE had more congenital anomalies (No IMID 9.8% vs SLE 13%), were smaller for gestational age (No IMID 12.5% vs SLE 16.1%) and had more NICU admissions (No IMID 9.6% vs SLE 20.2%). SLE prescription dispensations included corticosteroids 21%, NSAIDs 5.5%, antimalarials 46.6%, and pregnancy safe DMARDs 9.5%. Mean PDC for anti-malarials increased from 60.6 (SD 30.3) to 72.2 (SD 27.4) between 2008-2016 and 2017-2024. Preterm delivery was more common in women with SLE (17.4%) vs no IMID (7.0%). In multivariable models, factors that were significantly associated with higher risk of preterm delivery in women with SLE included: low PDC (< 40%) of anti-malarials (compared to high PDC (> 80%)); high PDC of corticosteroids (compared to no use); active disease, being married and pre-eclampsia/eclampsia (Table 1).

Conclusion Pregnancy-safe medication use has increased over time but peripartum outcomes remain poor for SLE women. Despite use in SLE flares, corticosteroid use may increase risk of preterm labor. Adherence to anti-malarial use during pregnancy may improve outcomes through reduction of flares. Further patient education and close disease monitoring in the peripartum period is recommended. Supported by a CIORA grant