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

Abstract Background Evidence regarding associations between maternal asthma medication use and birth defects is mixed. Objective Using National Birth Defects Prevention Study (NBDPS) data from 1997-2011, we estimated associations between asthma medication use and 52 specific birth defects. Methods We compared self-reported maternal asthma medication use for 28,481 birth defect cases and 10,894 non-malformed controls. We calculated adjusted odds ratios [95% confidence intervals] 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. Results Overall, 1,304 (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 [1.27-2.58]). Early pregnancy bronchodilator only use was associated with cleft palate (1.50 [1.11-2.02]), cleft lip (1.58 [1.12-2.23]), longitudinal limb deficiency (2.35 [1.55-3.54]), and truncus arteriosus (2.48 [1.13-5.42]). While 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 [1.55-8.35]) and pulmonary atresia (2.50 [1.09-5.78]). Conclusion Consistent with previous NBDPS 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, as early pregnancy asthma exacerbations have been associated with adverse birth outcomes, including birth defects.