Asthma in pregnancy and its pharmacologic treatment.

Background: Asthma is among the most common serious medical problems in pregnancy, and its prevalence may be increasing. Management is problematic because asthma may harm the fetus, yet little is known about fetal risks of asthma medications.

Objective: To examine the prevalence, symptom control, and pharmacologic treatment of asthma in pregnancy.

Methods: Study participants were a random sample of 3,609 mothers of nonmalformed infants born in Massachusetts between 1998 and 2006. Interviewed within 6 months of delivery, participants were asked specific asthma-related questions and classified as having physician-diagnosed, possible, past, or no asthma; those with physician-diagnosed asthma were classified as having well-controlled, not well-controlled, or poorly controlled asthma. Drug treatments were grouped into corticosteroids, beta(2)-agonists, leukotriene modifiers, combination products, and others.

Results: Physician-diagnosed asthma was present in 502 women (13.9%) and possible asthma in an additional 578(16.0%). Higher rates of asthma were observed among women who were younger, white, obese, and less well educated, had lower income, and smoked during pregnancy. Secular changes were unremarkable: leukotriene modifiers were used by only 3.4% of asthmatic women; inhaled steroid use increased only from 19.0% during 1997-1999 to 23.3% in 2003-2005, whereas use of inhaled beta(2)-agonists exceeded 50% in both periods. Less than 40% of women with poorly controlled asthma symptoms reported use of a controller medication.

Conclusions: High rates of asthma and asthma symptoms, together with the low rates of use of controller medications, underscore the need to better understand the risks and safety of asthma medications during pregnancy.