The Safety of Long-Acting β-Agonists for the Treatment of Asthma in Pregnancy: A Prospective Observational Study.

Abstract

Asthma is among the most common chronic diseases affecting pregnant women. In adults with uncontrolled asthma, the addition of a long-acting β-agonist (LABA) to inhaled corticosteroids (ICS) is more effective than increasing the dose of ICS for asthma control. However, data on the gestational safety of LABAs are limited. To evaluate the risk for major birth defects, small for gestational age (SGA), spontaneous abortion (SAB), and preterm delivery (PTD) in women using LABA during pregnancy. Participants in the United States or Canada were recruited between 2009 and 2014 by MotherToBaby Pregnancy Studies at UC San Diego. Pregnant women treated with LABAs, with or without ICS, were compared with those using short-acting β-agonists (SABAs), with or without ICS, and with those without asthma. Data on exposures and outcomes were collected through maternal interviews and medical records. A total of 439 participants were enrolled: 100 exposed to LABAs, 103 exposed to SABAs, and 236 nonasthmatic women. Liveborn infants of women exposed to LABAs were not significantly more likely to have major congenital malformations compared with either reference group (adjusted relative risk [aRR], 1.05; 95% confidence interval [CI], 0.32, 3.40; and aRR, 0.63; 95% CI, 0.23, 1.67, respectively). LABA exposure was no more likely to result in SAB, PTD, or SGA infants than in either comparison group. There was no significant increase in risk for the selected adverse outcomes in women exposed to LABAs during pregnancy.