New recommendation offered for timing of late preterm antenatal steroids
Gyamfi-Bannerman C, Thom EA, Blackwell SC, et al; for the NICHD Maternal-Fetal Medicine Units Network. Antenatal betamethasone for women at risk for late preterm delivery. N Engl J Med. 2016;374(14):1311-1320.
American College of Obstetricians and Gynecologists. Committee Opinion No. 677. Antenatal corticosteroidtherapy for fetal maturation. Obstet Gynecol. 2016;128(4):e187-e194.
Kamath-Rayne BD, Rozance PJ, Goldenberg RL, Jobe AH. Antenatal corticosteroids beyond 34 weeks gestation: what do we do now? Am J Obstet Gynecol. 2016;215(4):423-430.
A dramatic recommendation for obstetric practice change occurred in 2016: the option of administering antenatal steroids for fetal lung maturity after 34 weeks. In the Antenatal Late Preterm Steroids (ALPS) trial of betamethasone in the late preterm period in patients at "high risk" of imminent delivery, Gyamfi-Bannerman and colleagues demonstrated that the treated group had a significant decrease in the rate of neonatal respiratory complications.
The primary outcome, a composite of respiratory morbidities (including transient tachypnea of the newborn, surfactant use, and need for resuscitation at birth) within the first 72 hours of life, had significant differences between groups, occurring in 165 of 1,427 infants (11.6%) in the betamethasone-treated group and 202 of 1,400 (14.4%) in the placebo group (relative risk in the betamethasone group, 0.80; 95% confidence interval, 0.66-0.97; P = .02). However, there was no statistically significant difference in respiratory distress syndrome, apnea, or pneumonia between groups, and the significant difference noted in bronchopulmonary dysplasia was based on a total number of 11 cases.
In response to these findings, both the American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM) released practice advisories and interim updates, culminating in a final recommendation for a single course of betamethasone in patients at high risk of preterm delivery between 34 and 36 6/7 weeks who have not received a previous course.
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In a thorough review of the literature on antenatal steroid use, Kamath-Rayne and colleagues highlighted several factors that should be considered before adopting universal use of steroids at >34 weeks. These include:
- The definition of "high risk of imminent delivery" as preterm labor with at least 3-cm dilation or 75% effacement, or spontaneous rupture of membranes. The effect of less stringent inclusion criteria in real-world clinical practice is not known, and many patients who will go on to deliver at term will receive steroids unnecessarily.
- Multiple gestation, patients with pre-existing diabetes, women who had previously received a course of steroids, and fetuses with anomalies were excluded from the ALPS study. Use of antenatal steroids in these groups at >34 weeks should be evaluated before universal adoption.
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- The incidence of neonatal hypoglycemia in the treated group was significantly increased. This affects our colleagues in pediatrics considerably from a systems standpoint (need for changes to newborn protocols and communication between services).
- The long-term outcomes of patients exposed to steroids in the late preterm period are yet to be delineated, specifically, the potential neurodevelopmental effects of a medication known to alter preterm brain development as well as cardiovascular and metabolic consequences.