Disease Activity Trajectories During Pregnancy Predict Medically Indicated Complications in Women with Systemic Lupus Erythematosus

Background: Pregnancy in women with systemic lupus erythematosus (SLE) carries an increased risk of maternal and obstetric complications. Current risk assessment often relies on disease activity measured at a single time point and may not reflect dynamic changes during pregnancy. The clinical value of longitudinal disease activity trajectories remains insufficiently defined. Methods: We conducted a retrospective cohort study of 245 pregnancies in women with SLE managed at a tertiary referral center. Disease activity was assessed longitudinally and classified into three trajectories: persistent low activity, early flare with subsequent control, and uncontrolled disease activity during pregnancy. The primary outcome was a composite of clinically actionable maternal or obstetric complications prompting medical intervention. Multivariable logistic regression was performed to evaluate associations between disease activity trajectories and the primary outcome. Results: Clinically actionable pregnancy complications occurred in 41 out of 245 pregnancies (16.7%). The incidence differed significantly across disease activity trajectories, occurring in 3.9% of pregnancies with persistent low activity, 11.6% with early flare followed by control, and 63.8% with uncontrolled disease activity during pregnancy (p < 0.001). After adjustment for relevant covariates, uncontrolled disease activity remained strongly associated with the primary outcome (adjusted odds ratio 13.45, 95% confidence interval 4.01–45.08), whereas early flare with subsequent control was not associated with increased risk. Conclusions: Disease activity trajectories during pregnancy are strongly associated with clinically actionable pregnancy complications in women with SLE. Uncontrolled disease activity confers a markedly increased risk, while early disease flare followed by effective control does not. Trajectory-based assessment may improve risk stratification and support more individualized management during SLE pregnancies.