Eighty pregnancies in 73 gravidas with severe asthma who required inhaled and/or systemic corticosteroids were reported in an attempt to define the effects of asthma and its treatment on the outcome of pregnancy. No maternal deaths occurred. Infants delivered from gravidas who experienced at least one episode of status asthmaticus during gestation had decreased birth weights (p = 0.03) compared with infants delivered from gravidas who did not require emergency therapy or develop status asthmaticus. The data confirm the importance of maintaining gravidas with severe asthma as free from symptoms and signs of asthma as possible.