To determine the effect of corticosteroids, administered 24 to 48 hours before parturition, on the incidence of neonatal respiratory distress syndrome (RDS) and to determine whether the therapy has any adverse short- or long-term (up to 36 months) effects on the infant. Secondarily, to determine whether the therapy has any adverse short-term effects on the mother and to determine whether morbidity rates for neonatal respiratory distress syndrome as well as total and cause-specific infant mortality rates differ between mothers who received antenatal steroids and those who received conventional medical care.