The Association Between Use of Inhaled Corticosteroids and Long-Acting Beta2-Agonists During Pregnancy and Adverse Fetal Outcomes.

Background and objective: Women with asthma should continue controller therapy during pregnancy, but current evidence on the effects of inhaled corticosteroids (ICS) and long-acting beta2-agonists (LABA) on adverse fetal outcomes remains unclear.

Methods: This was a population-based retrospective cohort study. Data were derived from the Health and Welfare Database, Birth Certificate Application, and Maternal and Child Health Database in Taiwan, from January 1, 2007 to December 31, 2018. Pregnant women with asthma were enrolled. Three independent variables included ICS use, ICS dose-response effects, and LABA use during pregnancy. Adverse fetal outcomes included low birth weight, small for gestational age, preterm birth, and congenital anomalies. Propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) were used to adjust for confounders, including sociodemographics, comorbidities, comedications, and asthma severity. Logistic regression models were used to calculate adjusted odds ratios (aORs).

Results: There were 4538 pregnant women with asthma enrolled in this study. After adjustment, neither ICS nor LABA use was significantly associated with any adverse fetal outcomes. However, among women exposed to ICS, high-dose ICS use during pregnancy was associated with a significantly higher risk of congenital anomalies (aOR: 3.87; 95% CI: 1.29-11.60) within 1 year of delivery.

Conclusions: ICS or LABA use during pregnancy was not associated with the risk of adverse fetal outcomes. Pregnant women with asthma should be advised to maintain controller therapy and avoid potential allergens to reduce the need for high-dose ICS.