Asthma has been reported to occur in 0.4-1% of pregnant women. A number of clinical studies have attempted to clarify the effect of pregnancy on the course of asthma. Taken together, there is little consistent evidence that pregnancy profoundly influences the severity of asthma, except in occasional individuals. The goals of therapy in managing asthma in a pregnant women are identical to those in a nonpregnant woman with asthma. Management of pregnant women with asthma aims at preventing recurrent attacks of wheezing, acute severe asthmatic attacks, and respiratory failure. Recent studies suggest that inflammation in the airway walls may play an important role in the pathogenesis of asthma. It is increasingly apparent that several different cells, particularly eosinophils, lymphocytes, macrophages, produce a variety of mediators that interact in a complex way to produce a number of pathologic effects. Therefore, the primary treatment should involve antiinflammatory drugs. At present, inhaled corticosteroids appear to be the most effective therapy. Cromolyn sodium may also have an antiinflammatory effect. On the other hand, beta 2-sympathomimetics are the most effective bronchodilators available, followed by theophylline. None of these anti-asthma drugs is harmful in usual doses, to either woman or fetus.