Antenatal corticosteroids for very preterm deliveries

Abstract

Antenatal corticosteroids are standard of care for women at risk of preterm delivery. One might assume that we know which pregnancies benefit from the treatment. However, the randomized, controlled trials that were performed before 1990 included very few infants who were delivered prior to 28 weeks gestational age. There also is minimal information about efficacy beyond 34 weeks' gestation. For resource-rich environments, efficacy at very early gestations is the important question, but in resource-poor environments where very early gestational age infants seldom survive, possible benefits of antenatal corticosteroids in late-preterm infants are important. The morbidity from respiratory distress syndrome (RDS) and other transitional respiratory problems in late-preterm infants is significant. The NICHD Maternal Fetal Network has launched a very large trial to test if antenatal corticosteroids will benefit late-preterm infants. In contrast, there is not an equipoise in resource-rich environments to randomize very early deliveries and antenatal corticosteroids. However, there are larger epidemiological reports suggesting benefits of antenatal corticosteroids for very early gestational age deliveries to decrease both morbidities and mortality. For the present, we have only these clinical reports for assessing efficacy in very preterm infants, and recent clinical series report that 80%-90% of these pregnancies have received antenatal corticosteroids. The untreated pregnancies tend to be either very abnormal or deliver without sufficient time for treatment. Thus, there are not good comparison groups for the preterm infants exposed to corticosteroids outside of trials. The penetrance of antenatal corticosteroid use in Japan is low. In this issue of The Journal, Mori et al report for the Japanese Neonatal Research Network that 58% of 11 600 infants born between 22 and 33 weeks gestation were exposed to antenatal corticosteroids. They found that the corticosteroids decreased RDS, intraventricular hemorrhage (IVH), and survival for deliveries between about 24 and 29 weeks. Although there was no RDS or IVH benefit at 22-23 weeks gestation, survival was increased with maternal corticosteroid treatment. These outcomes are not based on randomized treatments, but they are the best information that we are likely have for the efficacy of antenatal corticosteroids for very early gestation infants. Article page 110▶ Antenatal Corticosteroids Promote Survival of Extremely Preterm Infants Born at 22 to 23 Weeks of GestationThe Journal of PediatricsVol. 159Issue 1PreviewTo evaluate the effectiveness of antenatal corticosteroid (ACS) to improve neonatal outcomes for infants born at <24 weeks of gestation. Full-Text PDF