Impact of Belimumab Exposure on Pregnancy Outcomes in Women with Lupus

A new study looked at available data on birth defects and loss of pregnancy (miscarriage or still-birth) in women who were using belimumab (Benlysta) for lupus treatment. Three data sources – clinical trial findings (18 total), the Belimumab Pregnancy Registry (BPR), and post-marketing reports – were analyzed to determine trends and outcomes of belimumab use in pregnant women with lupus. The data revealed inconclusive findings, and researchers determined that there is insufficient information currently available to make any associations between timing of belimumab exposure and birth defects or pregnancy loss.

Birth defect and pregnancy loss data in 319 women with lupus exposed to belimumab were analyzed. Across the three data sources, birth defects were identified in 5.6%, 21.7% and 1.1% of live births, respectively. In clinical trials, pregnancy loss occurred in 31.8% women in the belimumab-exposed group vs. 43.8% in the placebo group.

From the BPR data, 4.2% of women in the prospective group (enrolled in the registry before the end of pregnancy) experienced pregnancy loss whereas 50% of women in the retrospective group (enrolled in the registry after the pregnancy outcome occurred) had a pregnancy loss. And analysis of various reports found 31.4% pregnancy loss cases. No consistent pattern of birth defects or pregnancy loss was evident across datasets.

Pregnant women are typically excluded from enrolling in clinical trials for various reasons. Due to this lack of representation of pregnant women in clinical trials, there is limited information on the use of belimumab during pregnancy and any associated risk of birth defects or loss of pregnancy. As women with lupus are already at a heightened risk of pregnancy loss, further studies are needed to examine lupus treatments, such as belimumab and their association with birth defects and pregnancy loss. Learn more about lupus and pregnancy.

Read the study