Does antenatal corticosteroid therapy improve neonatal outcomes in late preterm birth?

Background: Infants who are born at 34^0/7 to 36^6/7 weeks of gestation (late preterm) are at greater risk for respiratory and other neonatal morbidities. The objective of this study was to examine the effects of administration of antenatal corticosteroids (ACSs) to women at risk for late preterm delivery on the incidence of neonatal outcomes.

Methods: This was a prospective cohort study of singleton gestations at risk of imminent delivery between 34^0/7 and 36^6/7 weeks. Neonatal outcomes were compared between mothers who received ACS and those who did not. Primary outcome was the rate of composite respiratory morbidity defined as the need for treatment within 72 h of life (continuous positive airway pressure or high flow nasal cannula for least 2 h or supplemental oxygen with a fraction of inspired oxygen of at least 0.30 for at least four continuous hours or mechanical ventilation).

Results: During the 3-year study period, 595 subjects were included in this study, comprising 234 subjects that received ACS and 361 that did not. Administration of ACS significantly reduced the rates of composite respiratory morbidity (adjusted odds ratio (aOR) 0.63, 95% confidence interval (CI) 0.40-0.99), the use of CPAP or HFNC for at least 2 h (aOR 0.57, 95% CI 0.35-0.94) and transient tachypnea of newborn (aOR 0.48, 95% CI 0.28-0.82). Neonatal hypoglycemia was more significantly increased in the ACS group compared with controls (aOR 1.64, 95% CI 1.04-2.59). We found no significant between-group differences in the rate of respiratory distress syndrome, surfactant use, need for resuscitation, jaundice requiring phototherapy, admission to neonatal intensive care or special care nursery and duration of hospitalization.

Conclusion: Administration of ACS during the late preterm period decreased neonatal respiratory complications, however, increased the rate of hypoglycemia.

Keywords: Antenatal corticosteroids; hypoglycemia; late preterm; respiratory morbidity; transient tachypnea of newborn.