Reassessing the role of antiphospholipid antibodies in placental‐mediated adverse pregnancy outcomes in systemic lupus erythematosus: A retrospective cohort study

OBJECTIVE: To examine how different antiphospholipid antibody (aPL) profiles influence placental-mediated adverse pregnancy outcomes (APOs) in women with systemic lupus erythematosus (SLE). METHODS: This retrospective cohort study included 245 pregnant women with SLE and 490 controls from a single center. Clinical features, immunologic markers and aPL profiles were analyzed. Logistic regression models were used to explore associations between antiphospholipid syndrome (APS), individual aPL subtypes, antibody burden and placental-mediated APOs. RESULTS: Placental-mediated APOs occurred more often in SLE pregnancies than in controls (27.8% vs. 9.8%). After adjustment, APS was not independently associated with APOs. Renal involvement, chronic hypertension and hypocomplementemia remained significant predictors (P < 0.05). Among antibody types, lupus anticoagulant (LAC) showed the strongest association in univariate analysis, but the effect weakened in multivariable analysis. Women with multiple aPL positivity had a higher risk of placental complications, whereas single positivity showed little independent effect. CONCLUSION: In SLE pregnancies, obstetric risk is not explained by APS alone. Antibody burden, especially multiple aPL positivity, together with renal disease, hypertension and complement levels appears more informative for assessing placental-related risk.