Current recommendations suggest that women who go into labor before 34 weeks gestation receive antenatal corticosteroids (betamethasone), which help the baby's lungs grow properly. However, some babies born between 34 and 36 weeks gestation need respiratory support right from birth.
Researchers from the Eunice Kennedy Shriver National Institute of Child and Human Development Maternal Fetal Medicine Units Network (MFMU) wanted to know if babies born at later gestational ages would benefit from antenatal corticosteroids, as well.
"For many years, obstetric and pediatric providers have known that steroids administered in preterm labor help speed the development of the preterm baby's lungs at 34 weeks gestation or earlier," said study author Dwight Rouse, a professor of obstetrics and gynecology at The Warren Alpert Medical School of Brown University. "This new research has shown that these same steroids when given to women who are at risk for late preterm delivery can significantly reduce the rate of neonatal respiratory complications."
The study involved a multicenter, randomized trial of nearly 2,800 pregnant women with one baby at 34 weeks to 36 weeks, five days gestation and at high risk for late preterm delivery. Participants were randomly assigned to either receive injections of betamethasone or a placebo 24 hours apart. Then, researchers looked to see if infants needed respiratory treatment in the first 72 hours following delivery.
Findings showed that about 14 percent of babies in the placebo group needed treatment when compared to about 12 percent of babies in the bethamethasone group. Researchers also found that severe respiratory complications occurred less frequently in the betamethasone group, including prolonged oxygen supplementation, surfactant use, mechanical ventilation and bronchopulmonary dysplasia, a chronic form of lung disease in newborns.
"This research supports the use of known medications that will allow us to help even more babies get the healthiest start at life," Rouse said. "I am proud of our hardworking MFMU Network research team for their dedication to this project. I am also very grateful for the contribution of Women & Infants' obstetricians and midwives, who gave their ongoing support to this study and encouraged their patients - to whom I am also profoundly grateful - to participate. As a result, Women & Infants contributed more than ten percent of the patients enrolled in this large trial, more than any other participating hospital."
The study is published today in the New England Journal of Medicine.
