The interval between a single course of antenatal steroids and delivery and its association with neonatal outcomes

This study was undertaken to determine whether the benefits of a single course of antenatal steroid treatment for neonatal respiratory morbidity diminish beyond 7 days.

A retrospective chart review was performed of all deliveries less than 34 weeks' gestation where delivery occurred after completing a single course of antenatal steroids (dexamethasone or betamethasone). Maternal and neonatal charts were reviewed, treatment course was confirmed, and neonatal morbidities were collected.

Of 197 neonates whose mothers received a full course of antenatal steroids, 98 delivered within 7 days and 99 delivered more than 7 days after the initial dose. The 2 groups were similar in gestational age at delivery (30 weeks 0 days vs 30 weeks 4 days). The groups were also similar in maternal age, race, payor status, type of steroid given, route of delivery, gender, and birth weight. Overall, infants delivering within 7 days had a lower incidence of receiving respiratory support for more than 24 hours (62% vs 81%, P < .01), but there were no significant differences between the groups in surfactant treatment (39% vs 47%), use of mechanical ventilation (49% vs 59%), necrotizing enterocolitis (6% vs 4%), intraventricular hemorrhage (15% vs 20%), oxygen dependence at 28 days (24% vs 23%) or at 36 weeks estimated gestational age (13% vs 12%), length of stay (34 days vs 38 days), or mortality (2 vs 0). These results were no different when evaluating only infants delivered before 30 weeks.

Among infants exposed to a single course of antenatal steroids, delivering more than 7 days after initiation of treatment was associated with an increased need for short-term respiratory support, but not other measures of neonatal morbidity. These data challenge the concept of diminishing efficacy of steroids after 7 days, and question the need for considering a rescue course.