We report on the outcome of 56 pregnancies in 51 women with severe asthma requiring prednisone and/or beclomethasone dipropionate. There were no malformations, neonatal deaths, or maternal deaths. The overall incidence of premature (less than 37 weeks gestational age) and low birth-weight infants (less than or equal to 2500 gr) was slightly higher than would be expected in the general population. These findings appeared attributable in part to infants of gravidas whose asthma was complicated by emergency room visits or status asthmaticus. There was a statistically increased incidence of low birth weight and small size for gestational age infants in the eight infants born to women who experienced status asthmaticus when these infants were compared to the 41 infants born to women who did not require emergency room therapy or develop status asthmaticus. Our data confirm that prednisone and beclomethasone dipropionate are appropriate therapy for pregnant women with severe asthma and suggest that the prevention of status asthmaticus may result in a favorable outcome for the fetus. The current study confirms previous evaluations of pregnant women with severe asthma conducted by Northwestern University Allergy Service and extends the series to 171 pregnancies.