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Antenatal corticosteroids reduce mortality risk for very premature infants

Corticosteroids were associated with a lower rate of mortality and morbidity in infants when administered to mothers as early as 23 weeks of pregnancy, with very premature babies benefiting most, according to a study in British Medical Journal.

“The current recommendations for infants at the lowest gestations are based on limited evidence from randomized controlled trials, but the extension of the recommendation to consider administration below 24 weeks is based on consensus and recent observational studies in selected populations,” Colm P. Travers, MD, from the division of neonatology at the University of Alabama at Birmingham, and colleagues wrote. “As some of the benefits of antenatal corticosteroids differ by gestational age, the objective of this study was to determine the presence and magnitude of the association between antenatal corticosteroids and outcomes at each gestational age for which this treatment is currently recommended.”

Previous research has shown that corticosteroids help infant development and increase the chance of survival in preterm infants. In this prospective cohort study, researchers assessed data for 117,941 infants born between 23 and 34 weeks of gestation from Jan. 1, 2009 to Dec. 31, 2013, at 300 neonatal intensive care units in the U.S. They analyzed death or major hospital morbidities by gestational age and exposure to antenatal corticosteroids, adjusting models for birth weight, sex, mode of delivery and multiple births.

The investigators found that the 81,832 preterm babies exposed to antenatal corticosteroids had a significantly lower rate of death before discharge at each gestation — 29 weeks or less, 31 weeks and 33-34 weeks — compared with babies without exposure. They also observed that the number of infants needed to treat with corticosteroids increased from six at 23 and 24 weeks’ gestation to 798 at 34 weeks’ gestation to prevent one death before discharge, suggesting that those born at the lowest gestational ages benefit most.

Among infants exposed to antenatal corticosteroids at the lowest gestations, the rate of survival without major hospital morbidity was higher. Newborns exposed to corticosteroids experienced lower rates of severe intracranial hemorrhage or death, necrotizing enterocolitis stage 2 or above or death, and severe retinopathy of prematurity or death compared with those without exposure at all gestations less than 30 weeks and most gestational ages at 30 weeks’ gestation or later.

“This study supports the administration of antenatal corticosteroids in women with threatened preterm labor from 23 to 34 weeks’ gestation,” Travers and colleagues wrote. “The effect on mortality and survival without major morbidities of exposure to antenatal corticosteroids seems to be largest in infants at the lowest gestations, including infants at 23 weeks’ gestation who were not included in randomized controlled trials.”

In a related commentary, Sarah D. McDonald, MD, FRCSC, MSc, professor in the departments of obstetrics and gynecology, radiology, and clinical epidemiology and biostatistics at McMaster University in Ontario, Canada, cautions that the benefits of antenatal corticosteroids at gestational ages before active resuscitation, which often occurs at 25 weeks in high income countries, needs further research.

“The new study did not report data on surfactant administration, the type of steroids administered, the number of doses used either antenatally or postnatally, or other factors that could affect neonatal outcomes such as infection during labor,” McDonald wrote. – by Savannah Demko

Disclosure: Travers reports receiving support from the Agency for Healthcare Research and Quality, the Perinatal Health and Human Development Research Program at the University of Alabama at Birmingham and the Children’s of Alabama Centennial Scholar Fund. Please see the full study for a list of all other authors’ relevant financial disclosures. McDonald reports no relevant financial disclosures.