Birth outcomes in severe asthma patients on biologic therapy: a retrospective analysis

Data on the safety of severe asthma biologics in pregnancy is limited. To provide insight into the safety of severe asthma biologics in pregnancy we examined birth outcomes in patients receiving biologics therapy to those not. A retrospective review of electronic medical records of patients attending a dedicated severe asthma pregnancy clinic between 2022-2024. We examined delivery dates and pregnancy outcomes. 29 patients were included (median age 32, QR 9.25). 17 (59%) were on biologic therapy at first visit, 16 (94%) continued throughout pregnancy, with 6 on Xolair, 1 on Mepolizumab, 7 on Benralizumab and 3 on Dupilumab. The 13 patients not on biologics had a median delivery date of 39 weeks (37-40). All were live births with no foetal abnormalities, 3 (23%) were vaginal deliveries, 6 (46%) elective caesarean sections, and 4 (31%) emergency caesarean sections. Of the 16 on biologic therapy, there was one miscarriage at 10 weeks. The median date of delivery was 36 weeks (25-39). All were live births with no foetal abnormalities, 4 (25%) were vaginal deliveries, 4 (25%) elective caesarean sections, and 7 (43%) emergency caesarean sections. All but one pregnancy resulted in live births with no foetal abnormalities in either the biologic or non-biologic groups. Those on biologic therapy had a lower average gestational age at delivery and higher rate of emergency caesarean sections compared to those not on biologic therapies. These findings demonstrate that biologic therapies are safe in pregnancy. Larger cohort studies are required to explore their potential impact on delivery method and timing. A major confounder is likely to be obstetricians’ assessment of risk of asthmatics on biologic.