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

Asthma is associated with adverse pregnancy and delivery outcomes. Stress, IgE sensitization, and lung function may contribute to these associations.

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.

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_A/L to airborne allergens) and perinatal outcomes were estimated by regression analyses. Z scores for forced expiratory volume in 1 second (FEV₁), forced vital capacity (FVC), and FEV₁/FVC ratio were used as exposures in secondary analyses. All analyses were adjusted for maternal stress on the bases of questionnaires, diagnoses, and medications.

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.

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.