Abstract:

BACKGROUND:Estimates of the effects of maternal asthma on pregnancy outcomes are inconsistent across studies, possibly due to differences in exposure definition. OBJECTIVE:To evaluate the risk of adverse perinatal outcomes associated with maternal asthma diagnosis, severity, and control in a large, nationally-representative cohort. STUDY DESIGN:This study was conducted within the IBM MarketScan database (2011-2015) and the Medicaid Analytic eXtract (MAX) database (2000-2014). Asthma was identified by diagnosis and treatment codes, severity was based on medications dispensed, and control was based on short-acting beta agonist dispensations and exacerbations. We estimated the relative risks (RRs) of stillbirth, spontaneous abortion, preterm birth, small for gestational age (SGA), neonatal intensive care unit (NICU) admission, and congenital malformations, comparing pregnancies with differing asthma disease status. RESULTS:We identified 29,882 pregnancies complicated by asthma in MarketScan and 160,638 in MAX. We observed no consistent associations between asthma diagnosis, severity, or control, and stillbirth, abortions, or malformations. However, we observed increased risks of prematurity, SGA, and NICU admission among women with asthma compared to those without asthma. Compared to women with well-controlled asthma, women with poor control late in pregnancy had an increased risk of preterm birth (RR=1.39; 95% Confidence Interval: 1.32-1.46) and NICU admission (1.26; 1.17-1.35). More severe asthma was associated with SGA (1.18; 1.07-1.30). CONCLUSION:We did not observe an increased risk of pregnancy losses or malformations among women with asthma. However, we found an association between asthma severity and SGA; and between exacerbations late in pregnancy and preterm delivery and NICU admission.