Monoclonal Antibodies in Pregnancy of Patients with Systemic Lupus Erythematosus: Friend or Foe? A Case Report of a Patient with Multiple Pregnancies.

Systemic lupus erythematosus (SLE) is an autoimmune disease that predominantly affects women of childbearing age, and active disease during pregnancy is associated with increased maternal and fetal morbidity. Belimumab is an effective biologic therapy for active SLE; however, its use during pregnancy has long been limited by the scarcity of safety data. Recent evidence and updated international recommendations suggest that belimumab may be considered in selected cases when required to maintain maternal disease control. We report the case of a woman with SLE who experienced three consecutive pregnancies with live births between 2019 and 2024 while receiving belimumab, allowing an intra-individual comparison of different exposure strategies. During the first pregnancy, belimumab was discontinued at conception and was followed by a disease flare in late pregnancy and postpartum. In the second and third pregnancies, belimumab was continued until gestational week 20 following shared decision-making with the patient; nevertheless, disease flares occurred during the third trimester of both pregnancies. All pregnancies resulted in live births at term, with no congenital anomalies, placental insufficiency, or fetal growth restriction. One neonate from the third pregnancy developed early-onset neonatal sepsis and meningitis, which resolved completely after antibiotic treatment. All children are currently growing and developing normally. This case supports a risk-adapted approach to belimumab use during pregnancy. In selected women with SLE at high risk of disease reactivation, continuation of belimumab until mid-gestation may contribute to improved maternal disease control without evident adverse fetal outcomes.