Pharmacologic enhancement of fetal lung maturation.

During the 22 years since the first clinical reports of prenatal corticosteroid treatment to enhance fetal lung maturation, this treatment has been studied in thousands of preterm newborns. These studies demonstrated that prenatal steroid treatment reduces RDS among premature newborns at 26 to 33 weeks gestation. The potent fluorinated steroids, betamethasone and dexamethasone, are more effective in accelerating lung maturation than are the less potent corticosteroids, cortisol, cortisone, and prednisone. No immediate or long-term adverse effects have been demonstrated for the newborn or fetus. With PROM, mothers may have an increased risk of endometritis without a clear increase in overall frequency of infection, at the same time steroids significantly decrease the frequency of RDS in the newborns. During these 22 years of evaluation and application of prenatal steroid treatment to reduce RDS, the survival of the very low birth weight (< 1501 g) newborn has increased dramatically. Major morbidities, however, impact significantly on the quality of life for these survivors with birth weights as low as 500 g and gestations as short as 22 to 23 weeks. Prenatal steroid treatment reduces the frequency of PDA, intraventricular hemorrhage, NEC, and bronchopulmonary dysplasia. These are the most important and frequent morbidities that reduce the quality of life for the very low birth weight survivor. Without clearly demonstrable and major adverse effects for the mother or child from corticosteroid treatment, the cost/benefit ratio strongly and clearly favors treatment when preterm delivery is anticipated. Hopefully, obstetricians will use corticosteroids more often in the management of preterm labor because this treatment may markedly improve the quality of survival for many premature newborns.