Factors Associated with Nonadherence to Inhaled Corticosteroids for Asthma During Pregnancy

Nonadherence is common among pregnant women prescribed inhaled corticosteroids (ICS) for asthma and may have serious consequences for mother and baby. Factors associated with ICS nonadherence have not been determined in this population.

To determine factors associated with {1} nonadherence to ICS in early-mid pregnancy (cross-sectional) and {2} persistent nonadherence to ICS during pregnancy (longitudinal).

Data used come from 3 prospective studies (2004-2019) involving women with asthma recruited by 23 weeks' gestation (N = 1614). Demographics, asthma history, and current symptoms were assessed, and spirometry was performed at baseline and throughout pregnancy. Women self-reported current medication use and number of ICS doses missed in the past week. Nonadherence was defined as ≥20% of prescribed dosages missed in the past week (baseline) and on at least 2 occasions during follow-up (persistent). Factors associated with ICS nonadherence were examined using backward stepwise logistic regression.

Of 610 (38%) women prescribed ICS at baseline, 236 (39%) were classified as nonadherent. Of 612 (38%) women prescribed ICS during at least 2 follow-up visits, 149 (24%) were classified as persistent nonadherent. Factors associated with nonadherence at baseline were current or ex-smoking, non-Caucasian/non-Indigenous ethnicity, adult diagnosis of asthma, and lower lung function. Factors associated with persistent nonadherence to ICS were lower maternal age, higher parity, and no prescribed ICS at baseline.

Young multiparous non-Caucasian/non-Indigenous mothers are at increased risk of being nonadherent to ICS during pregnancy. Strategies to improve ICS nonadherence should address maternal smoking and target women who (re-)initiate ICS use in pregnancy.