Factors Associated with Asthma Exacerbations During Pregnancy

Background Asthma exacerbations during pregnancy are associated with adverse pregnancy outcomes. Objective The aim of this study was to establish factors associated with asthma exacerbations during pregnancy. Methods We obtained data from three cohorts of pregnant women with asthma recruited in eastern Australia (2004-2019; n = 1461). Severe exacerbations were defined as episodes of asthma requiring hospitalization, an emergency department visit, or prescription of oral corticosteroids after enrollment. Baseline information on potential risk factors included demographic characteristics, asthma characteristics (eg, lung function, asthma triggers, asthma control, medication use), pregnancy factors (eg, fetal sex, parity, antenatal care type), and other maternal factors (body mass index, smoking status, mental health). Backward stepwise logistic regression and Akaike information criterion were used to determine the best-fitting model. Results A total of 135 participants experienced a severe exacerbation during pregnancy (9.2%). Medium to high ICS dose was most strongly associated with severe asthma exacerbations (adjusted odds ratio = 3.20; 95% confidence interval, 1.85-5.53). Worse asthma control, possession of a written action plan, and a history of asthma exacerbations in the year preceding pregnancy were associated with an increased rate of exacerbations. Conclusions Asthma exacerbations before pregnancy and more severe asthma at the beginning of pregnancy were associated with an increased rate of exacerbations during pregnancy. Despite Global Initiative for Asthma step 3 and 4 treatment and optimal management including a written asthma action plan, there is still a significant asthma burden in a group of women at high risk for severe exacerbations in pregnancy.