Pregnancy outcomes in patients treated with belimumab: Report from real-world experience

Objective To investigate the neonatal and maternal outcomes of patients treated with belimumab during pregnancy. Materials and methods We retrospectively collected patients who were treated with belimumab during pregnancy from January 2018 to October 2020 in a tertiary referral hospital in Taiwan. All patients had clinical and serological features of systemic lupus erythematosus or antiphospholipid syndrome and had been treated accordingly. The patients’ medical and obstetric history, obstetric complications and fetal outcomes were collected by chart review. Results A total of 13 pregnancies in 13 patients were included. The median age was 38 years (interquartile range 32–41 years), 46.2% had a history of recurrent pregnancy loss, and the median number of treatment courses with belimumab (400 mg per dose) was two. There were 11 live births (84.6%, 11 of 13). One episode of omphalitis was noted in one fetus, who recovered well with antibiotic treatment. No fetus had leukopenia, lymphopenia, neutropenia, or thrombocytopenia in the days after birth. No fetal anomalies were found in this series. Among the six patients with a past history of recurrent pregnancy loss, four had live births. Conclusion This study provides new evidence for the use of belimumab in pregnant patients. No increase in the risk of fetal anomalies or severe infection was noted in the patients who were exposed to belimumab during pregnancy. Cautious monitoring is necessary if belimumab is used in pregnant patients, and more data are still needed to validate its safety.