Maternal asthma and the role of stress, sensitization, and lung function on pregnancy outcomes: MAESTRO cohort study.

Background: Asthma is associated with adverse pregnancy and delivery outcomes. Stress, IgE sensitization, and lung function may contribute to these associations. Objective: We investigated the effect of allergy and stress on the association between maternal asthma and adverse outcomes; and examined the association between lung function and adverse perinatal outcomes. Methods: In the MAESTRO cohort of pregnant women recruited from urban antenatal clinics 2011-16, 1511 singleton pregnancies were followed to delivery (3.5% preterm), and 242 underwent spirometry. Asthma diagnosis and medication from national registers were linked to cohort data. Associations between allergic and nonallergic asthma (with and without IgE sensitization ≥ 0.35 kU Results: Eighteen percent (n = 293) of women had asthma; 60% of these had allergic asthma. Compared to women without asthma, allergic asthma was associated with reduced mean gestational age by 0.23 weeks (95% confidence interval, -0.44, -0.03). No other adverse perinatal associations were found for allergic asthma, and none was found for nonallergic asthma. Stress did not appear to affect the associations. Of women who underwent spirometry, 89% (n = 215) had normal lung function, and we detected no significant associations between lung function and adverse outcomes. Conclusion: Allergic asthma is associated with slightly lower gestational age. In women with normal lung function ranges, there is likely no association with adverse perinatal outcomes.