The impact of anti-SSA/Ro antibodies on pregnancy outcomes in patients with systemic lupus erythematosus

Abstract Objective We aimed to investigate the influence of anti-SSA/Ro antibodies and other factors on adverse pregnancy outcomes (APOs) in systemic lupus erythematosus (SLE) patients. Methods We retrospectively extracted first pregnancies after SLE onset from the Lupus Registry of Nationwide Institutions (LUNA, 2016–2022, n = 1775). We excluded patients with unclear anti-SSA/Ro status or pregnancy outcomes and cases of abortion. We used two-group comparison and logistic regression, adjusting for antiphospholipid antibodies (aPL), to analyse factors related to APOs and the influence of anti-SSA/Ro antibodies. Results The 247 pregnancies included 194 live births (122 full-term, 57 preterm, 15 unclear) and 53 fetal losses. Multivariate logistic regression showed fetal loss was associated with aPL (Odds ratio 95% confidence intervals, 2.46 1.21–5.01) and a history of methylprednisolone pulse (2.89 1.39–6.00), but not anti-SSA/Ro (1.32 0.64–2.74). No differences were found between anti-SSA/Ro positive (n = 145) and negative (n = 102) groups regarding live birth (anti-SSA/Ro positive vs negative, 77% vs 80%, p= 0.64) or preterm birth (31% vs 33%, p= 0.87). Clinical outcomes in a small subgroup were as follows (anti-SSA/Ro positive vs negative): birthweight, 2402 ± 586 g vs 2608 ± 449 g (p= 0.20); small for gestational age infants, 50% vs 8% (p= 0.11); and low birthweight infants, 67% vs 38% (p= 0.25). Conclusion aPL showed an association with fetal loss in SLE, while anti-SSA/Ro antibodies did not. Anti-SSA/Ro may influence fetal development, necessitating further researches.