Premature babies face a myriad of challenges once they leave their mother's womb. Most often preemies struggle with temperature regulation and weight gain, while some have an increased risk of developing severe respiratory problems. The results of a recent clinical trial, however, finds mothers at risk for late preterm delivery may be able to reduce complications with corticosteroids.

Late preterm delivery refers to babies born between 34 and 36 weeks of gestation, while early term delivery is between 36 and 37 weeks of gestation, the American College of Obstetricians and Gynecologists (ACOG) reported. ACOG and the Society for Maternal-Fetal Medicine "have long discouraged [non-medically indicated] delivery before 39 weeks of gestation" for potential uterine, fetal, and maternal complications it can cause. So if steroids can reduce complications associated with late term delivery, the present study's findings could change clinical care for at-risk mothers.

"Our study demonstrates that administering a medication that is commonly used to prevent complications in babies born before 34 weeks of gestation can also reduce the risk of many serious complications in babies delivered just a few weeks before term," lead investigator Dr. Cynthia Gyamfi-Bannerman, an associate professor of women's health at Columbia University Medical Center (CUMC) and obstetrician and maternal-fetal medicine specialist at New York Presbyterian (NYP), said in a statement. She worked alongside her colleagues from CUMC and NYP hospital.

Corticosteroids have been administered to at-risk mothers since the early 90s. The medication is meant to fast-track fetal lung development, so that once it arrives, the baby has an easier time absorbing oxygen and clearing unnecessary fluids. While some studies show 99 percent of babies born after 34-35 weeks survive, others suggest babies born after this point experience more neonatal and childhood respiratory complications compared to newborns born 37 weeks or later.

Approximately 8 percent (about 300,000 babies) are born during the late preterm period (34-36 weeks gestation) every year, the Centers for Disease Control and Prevention reported. Among these births, about 12 percent require persistent respiratory support or have other serious neonatal complications.

Gyamfi-Bannerman and her colleagues at CUMC and NYP hospital enrolled more than 2,800 pregnant women at risk for late preterm delivery to randomly receive two injections of a steroid called betamethasone or a placebo. They found that babies whose mothers were injected with the steroid faced lower risk of severe respiratory complications immediately after birth than babies whose mothers were injected with a placebo. Specifically, steroid injections significantly lowered a baby's risk for bronchopulmonary dysplasia, a lung condition that increases the risk of chronic lung disease later in childhood, than did placebo injections.

In addition, babies whose mothers were given steroids were less likely to need a long-term hospital stay in neonatal intensive or immediate care, or to require a respiratory treatment such as surfactant.

"While survival among late preterm infants is comparable to that of babies born at term, the rate of respiratory problems and other serious complications in this group is not comparable and remains unacceptably high," Gyamfi-Bannerman said. "Expanding the use of a well-studied, safe medication to improve lung development before birth offers a means of preventing many of these complications."

The researchers plan to dig deeper into steroid use, and determine if giving corticosteroids to mothers at risk for late preterm deliveries lowers their child's risk of long-term health problems.

Source: Gyamfi-Bannerman C, Thorn E, Blackwell S, Tita A, Reddy U, Saade G, et al. antenatal Late Preterm Steroids (ALPS): a Randomized Trial to Reduce Neonatal Respiratory Morbidity. New England Journal of Medicine. 2016.