Inhaled steroids are recommended for the treatment of persistent asthma during pregnancy, but their potential effects on intrauterine growth have been inadequately evaluated.

The purpose of this study was to evaluate the association between maternal use of specific inhaled steroids and inhaled steroid dose during pregnancy and the incidence of infants who are small for gestational age (SGA) and mean birth weight.

Pregnant asthmatic women being treated with inhaled steroids were enrolled in the study before delivery by their managing allergists. Information regarding the specific inhaled steroid and daily dose used, requirement for oral steroids, occurrence of acute asthmatic episodes, maternal race, birth weight, gestational age, and congenital malformations was obtained for each patient. SGA was defined through use of a published normative sample of American births.

A total of 474 women were enrolled in the study; of the 451 enrolled participants whose pregnancy ended in a singleton live birth, 396 (88%) completed the study. The incidence of infants with low birth weight, preterm births, and congenital malformations in this cohort was not greater than expected in the general population. The incidence of SGA was 7.1% (95% CI, 5.0% to 10.1%). No significant relationships between specific inhaled steroid or dose of inhaled steroid used and either SGA or mean birth weight were observed.

These data suggest that the use of inhaled steroids by pregnant asthmatic women does not reduce intrauterine growth and supports the recommendation that inhaled steroids should be used in the management of persistent asthma during pregnancy.