Impact of Asthma Medications During Pregnancy on Asthma Exacerbation, Maternal, and Neonatal Outcomes

Background Asthma affects 5% to 13% of pregnant women, and many require daily pharmacotherapy to achieve asthma control; however, adherence to medication during pregnancy often decreases. Objective To understand the association between the use of or adherence to asthma medication with asthma exacerbation and maternal/neonatal outcomes. Methods Using linked population-based administrative databases from Alberta, Canada (2012-2018), pregnant women with asthma were categorized based on asthma medication use 1 year before pregnancy: short-acting β-agonists (SABA), inhaled corticosteroids (ICS), and ICS with long-acting β-agonists (ICS+LABA). Women on ICS+LABA were grouped by trajectory of adherence during pregnancy using group-based trajectory modeling. Logistic regressions were used to estimate the associations between the use of or trajectories of adherence to asthma medication during pregnancy with asthma exacerbation and maternal/neonatal outcomes. Results Overall, 13,509 of 238,751 (5.7%) pregnant women had asthma before pregnancy (SABA: 24.7%; ICS: 12.5%; ICS+LABA: 25.1%; none: 36.1%). The use of SABA (adjusted odds ratio [aOR]: 1.79, 95% confidence interval [CI]: 1.21, 2.64), ICS (aOR: 3.37, 95% CI: 2.10, 5.39), and ICS+LABA (aOR: 3.64, 95% CI: 2.57, 5.17) had greater odds of disease exacerbation than no asthma medication during pregnancy. ICS+LABA adherence groups during pregnancy included low (79.8%), moderate-to-decreasing (14.0%), and moderate-to-increasing (6.2%). The moderate-to-decreasing (aOR: 1.45, 95% CI: 1.14, 1.84) and moderate-to-increasing (aOR: 2.06, 95% CI: 1.50, 2.83) adherence groups had greater odds of disease exacerbation than the low adherence group. ICS use during pregnancy decreased odds of preterm birth (aOR: 0.62; 95% CI: 0.39, 0.99) and neonatal intensive care unit admission (aOR: 0.66; 95% CI: 0.45, 0.97). Other group comparisons were not statistically significant. Conclusions Our study shows the importance of continuing asthma maintenance medication during pregnancy to improve outcomes. Future research should study the postpartum and long-term outcomes with asthma medication during pregnancy.