Asthma and pregnancy: a review of two decades

The prevalence of asthma among pregnant women varies among studies from 4 to 8%, making it by far the most common respiratory disorder complicating pregnancy. Controversy exists among the numerous retrospective and prospective studies regarding pregnancy outcomes of asthmatic patients. Overall, the literature indicates that women with severe asthma are at an increased risk for preterm delivery, low birth weight, preeclampsia and Caesarean delivery, especially in the absence of inhaled corticosteroid therapy. Asthmatic women carrying a female fetus may particularly be at increased risk of these adverse outcomes. On the other hand, mild or moderate, well-controlled asthma is associated with favorable pregnancy and perinatal outcomes. Pregnancy also influences the course of asthma. Recently published data indicate that the real risk for an exacerbation during pregnancy may be underestimated. There is no question, however, that the risk of having an exacerbation correlates closely with the severity of asthma. The mechanisms responsible for these changes are not fully understood. Maternal hypoxia or inflammatory processes have been suggested and could explain reduced fetal growth through alterations in placental function. The goal of asthma therapy is to maintain adequate oxygenation of the fetus by prevention of exacerbations. Optimal management of asthma during pregnancy should include scheduled monitoring of objective lung function tests, avoiding triggers, patient education and tailored pharmacologic therapy. Inhaled corticosteroids are the treatment of choice for all levels of persistent asthma, yet other drug classes, such as beta(2)-agonists and theophylline, are effective and safe for use during pregnancy.