The Safety of Biologic Treatment for Asthma in Pregnancy

Poorly controlled asthma during pregnancy has been associated with adverse maternal and neonatal outcomes. Biologic medications, such as mAbs, can improve control and reduce exacerbations in patients with moderate to severe asthma. However, there is limited data about the safety of biologics during pregnancy.

To determine the frequency of adverse pregnancy outcomes in patients with moderate to severe persistent asthma prescribed biologic therapies compared with an unexposed disease-matched cohort.

This is a retrospective cohort study using the TriNetX US Collaborative Network. Pregnant women aged 15 to 44 years with moderate to severe asthma between January 2010 and July 2025 were identified. The study included 2 groups, the asthma biologic prescription group and unexposed asthma controls, which were 1:1 propensity score-matched by age, race, ethnicity, comorbidities, substance use, and obesity. Primary outcomes were defined as maternal and fetal complications that occurred in relation to the index event (pregnancy date). Odds ratios with 95% CIs were calculated between matched groups for each outcome.

After propensity score matching, there were 535 pregnant patients in each group. There was a decreased risk of any adverse pregnancy outcome in the asthma biologic prescription group when compared with the disease-matched control group (odds ratio, 0.609; 95% CI, 0.460-0.807; P = .001).

Prescribed biologics for the treatment of moderate to severe asthma during pregnancy were not associated with an increased risk for adverse pregnancy outcomes when compared with disease-matched controls, and may have a protective effect in reducing adverse pregnancy outcomes.