Asthma Medication Use and Risk of Birth Defects: National Birth Defects Prevention Study, 1997-2011.

backgroundEvidence regarding associations between maternal asthma medication use and birth defects is mixed.

objectiveEstimate associations between asthma medciation use and 52 birth defects using National Birth Defects Prevention Study data from 1997 to 2011.

methodsWe compared self-reported maternal asthma medication use for 28,481 birth defect cases and 10,894 nonmalformed controls. We calculated adjusted odds ratios (95% CIs) to estimate the risk of birth defects associated with early pregnancy asthma medication use (the month before through the third month of pregnancy), controlling for maternal age, race/ethnicity, body mass index, smoking, folic acid-containing supplement use, and parity. We calculated risks by medication groupings: bronchodilators, anti-inflammatories, and both.

resultsOverall, 1304 (5%) case and 449 (4%) control women reported early pregnancy asthma medication use. We observed an association between asthma medication use and longitudinal limb deficiency (1.81; 95% CI, 1.27-2.58). Early pregnancy bronchodilator-only use was associated with cleft palate (1.50; 95% CI, 1.11-2.02), cleft lip (1.58; 95% CI, 1.12-2.23), longitudinal limb deficiency (2.35; 95% CI, 1.55-3.54), and truncus arteriosus (2.48; 95% CI, 1.13-5.42). Although early pregnancy anti-inflammatory-only use was not associated with the birth defects studied, use of both medications was associated with biliary atresia (3.60; 95% CI, 1.55-8.35) and pulmonary atresia (2.50; 95% CI, 1.09-5.78).

conclusionsConsistent with previous National Birth Defects Prevention Study analyses, asthma medication use was not associated with most birth defects examined, but we observed modest risks for bronchodilator use and several birth defects. Our findings support maintaining adequate asthma treatment during pregnancy, because early pregnancy asthma exacerbations have been associated with adverse birth outcomes, including birth defects.