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Published on: November 20, 2015
Antenatal Betamethasone for Women at Risk for Late Preterm Delivery
Cynthia Gyamfi-Bannerman1, Elizabeth A Thom1, Sean C Blackwell1
1From Columbia University, New York (C.G.-B.); the George Washington University Biostatistics Center, Washington, DC (E.A.T.); the University of Texas Health Science Center at Children's Memorial Hermann Hospital, Houston (S.C.B.), the University of Texas Medical Branch, Galveston (G.R.S.), and the University of Texas Southwestern Medical Center, Dallas (B.M.C.) - all in Texas; the University of Alabama at Birmingham, Birmingham (A.T.N.T.); the Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD (U.M.R.); Brown University, Providence, RI (D.J.R.); Ohio State University, Columbus (D.S.M.), and the MetroHealth Medical Center, Case Western Reserve University, Cleveland (E.K.C.) - both in Ohio; the University of Utah Health Sciences Center, Salt Lake City (E.A.S.C.); the University of North Carolina at Chapel Hill, Chapel Hill (J.M.T.), and Duke University, Durham (G.K.S.) - both in North Carolina; Northwestern University, Chicago (A.M.P.); the University of Colorado School of Medicine, Anschutz Medical Campus, Aurora (R.S.G.); Stanford University, Stanford, CA (M.E.N.); University of Pittsburgh, Pittsburgh (S.N.C.); Oregon Health and Science University, Portland (J.E.T.); Wayne State University, Detroit (Y.S.); the Medical University of South Carolina, Charleston (J.P.V.); and Emory University, Atlanta (L.J.).
Background:
Infants who are born at 34 to 36 weeks of gestation (late preterm) are at greater risk for adverse respiratory and other outcomes than those born at 37 weeks of gestation or later. It is not known whether betamethasone administered to women at risk for late preterm delivery decreases the risks of neonatal morbidities.
Methods:
We conducted a multicenter, randomized trial involving women with a singleton pregnancy at 34 weeks 0 days to 36 weeks 5 days of gestation who were at high risk for delivery during the late preterm period (up to 36 weeks 6 days). The participants were assigned to receive two injections of betamethasone or matching placebo 24 hours apart. The primary outcome was a neonatal composite of treatment in the first 72 hours (the use of continuous positive airway pressure or high-flow nasal cannula for at least 2 hours, supplemental oxygen with a fraction of inspired oxygen of at least 0.30 for at least 4 hours, extracorporeal membrane oxygenation, or mechanical ventilation) or stillbirth or neonatal death within 72 hours after delivery.
Results:
The primary outcome occurred in 165 of 1427 infants (11.6%) in the betamethasone group and 202 of 1400 (14.4%) in the placebo group (relative risk in the betamethasone group, 0.80; 95% confidence interval [CI], 0.66 to 0.97; P=0.02). Severe respiratory complications, transient tachypnea of the newborn, surfactant use, and bronchopulmonary dysplasia also occurred significantly less frequently in the betamethasone group. There were no significant between-group differences in the incidence of chorioamnionitis or neonatal sepsis. Neonatal hypoglycemia was more common in the betamethasone group than in the placebo group (24.0% vs. 15.0%; relative risk, 1.60; 95% CI, 1.37 to 1.87; P<0.001).
Conclusions:
Administration of betamethasone to women at risk for late preterm delivery significantly reduced the rate of neonatal respiratory complications. (Funded by the National Heart, Lung, and Blood Institute and the Eunice Kennedy Shriver National Institute of Child Health and Human Development; ClinicalTrials.gov number, NCT01222247.).
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