RESEARCH TRIANGLE PARK, N.C. — Using antenatal corticosteroid therapy for mothers of infants born at 23 to 25 weeks' gestation was associated with a lower rate of infant death or neurodevelopmental impairment at 18 to 22 months of age, according to a study in the December 7 issue of JAMA.
RTI International researchers co-authored the paper and served as the data coordinating center for the study led by researchers from the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network.
"Current guidelines, initially published in 1995, recommend antenatal corticosteroids for mothers with preterm labor from 24 to 34 weeks' gestational age, but not before 24 weeks due to lack of data. However, many infants born before 24 weeks' gestation are provided intensive care," according to the article.
The study was conducted to determine if antenatal corticosteroid exposure in very preterm infants was associated with improvement in outcomes that included death or childhood neurodevelopmental impairment at 18 to 22 months.
The study included data on more than 10,000 infants with a birth weight between 401 grams (14.1 ounces) and 1,000 grams (35.3 ounces) born at 22 to 25 weeks' gestation between January 1993 and December 2009 at 23 academic perinatal centers in the United States. Of these infants, 7,808 (74.1 percent) were born to mothers who received antenatal corticosteroids. Of the 5,691 infants born between 1993 and 2008 who survived to 18 to 22 months, 4,924 (86.5 percent) had neurodevelopmental assessments.
The researchers found that death or neurodevelopmental impairment was less frequent in those infants who had been exposed to antenatal corticosteroids and were born at 23 weeks' gestation (83.4 percent vs. 90.5 percent without exposure); at 24 weeks' gestation (68.4 percent vs. 80.3 percent); and at 25 weeks' gestation (52.7 percent with exposure to antenatal corticosteroids vs. 67.9 percent without exposure); but not in those born at 22 weeks' gestation (90.2 percent vs. 93.1 percent).
"If the mothers had received antenatal corticosteroids, the following events occurred significantly less in infants born at 23, 24, and 25 weeks' gestation: death by 18 to 22 months; hospital death; death, intraventricular hemorrhage, or periventricular leukomalacia (a type of brain injury); and death or necrotizing enterocolitis (a condition in which part of the tissue in the intestines is destroyed). For infants born at 22 weeks' gestation, the only outcome that occurred significantly less was death or necrotizing enterocolitis (73.5 percent with exposure to antenatal corticosteroids vs. 84.5 percent without exposure)," the authors wrote.
However, the authors caution that "even though intact survival doubled with the administration of antenatal steroids in the entire cohort, it remained relatively low (36 percent)."
"Despite their potential to improve outcomes, the administration of antenatal corticosteroids is not increasing at gestational ages around the limits of viability and remains substantially lower than at later gestational ages. Controlled trials could be performed to precisely determine the benefits of antenatal corticosteroids when administered this early, but such trials will be difficult to perform. Initiation of antenatal corticosteroids may be considered starting at 23 weeks' gestation and later if the infant will be given intensive care because this therapy is associated with reduced mortality and morbidity," the researchers conclude.