Women with inadequately treated asthma during pregnancy are at increased risk for premature delivery, according to a new study.

Medications to treat asthma are often restricted during pregnancy out of concern for potential harm to the developing child, even though there is evidence that severe asthma may have a harmful impact on mom and baby.

Dr. Ludmila N. Bakhireva, from the University of New Mexico in Albuquerque, and her associates studied the potential adverse effects of poorly controlled asthma in 719 pregnant women enrolled in their “Asthma Medication in Pregnancy Study” between 1998 and 2003.

They found that the incidence of preterm delivery was significantly higher among women with poorly controlled asthma during the first 20 weeks of pregnancy (11.4 percent versus 6.3 percent). The investigators defined poor asthma control as the presence during the prior 2 weeks of asthma symptoms that interfered with sleep or activity.

The incidence of preterm delivery was more than doubled among women hospitalized for asthma during any part of the pregnancy (16.4 percent versus 7.6 percent).

These findings highlight “the need to optimize asthma control and prevent asthma exacerbations… by avoidance of triggering factors, self-management education, and optimal pharmacotherapy,” the study team concludes.

SOURCE: Annals of Allergy, Asthma and Immunology, August 2008.