Antenatal corticosteroid therapy to prevent respiratory distress syndrome.

The recent National Institutes of Health Consensus Development Conference on ANS was strongly supportive of the use of ANS, even for 24 hours but, if possible, for 48 hours, in all fetuses between 24 and 34 weeks of gestation and at risk of preterm delivery regardless of race, gender, or the availability of surfactant replacement. For preterm rupture of membranes at less than 30 to 32 weeks, the use of ANS was also recommended in the absence of amnionitis, and patients eligible for tocolytic therapy were also deemed eligible for ANS. Thus the currently available literature indicates that pediatricians should encourage obstetricians to provide ANS in high-risk pregnancies, as outlined in the proposed National Institutes of Health guidelines. Even if a full 48-hour course of ANS cannot be achieved, ANS given less than 24 hours before delivery is associated with a decreased incidence of intraventricular hemorrhage and periventricular leukomalacia. In addition, we propose that investigators, reviewers, and editors ensure uniformly high maternal ANS exposure, consistent with the realities of clinical practice, when designing, evaluating, and publishing clinical trials with outcomes (e.g., RDS, intraventricular hemorrhage, periventricular leukomalacia, bronchopulmonary dysplasia, and death) that can be significantly affected by ANS. Otherwise, studies will continue to be performed on infants who, as fetuses, were deprived of treatment that may have prevented or ameliorated the disorder being assessed. Studies with an infrequent use of ANS may not be applicable or generalizable to an era when the use of ANS is an essential part of perinatal practice. Future trials should document both ANS use and the reasons for failure to achieve an acceptable level of such treatment.