1. Wisner, Kirsten MS, RNC, CNS

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Antenatal corticosteroids for women <34 weeks' gestation at risk of preterm birth within the next 7 days has been the standard of care since the mid 1990s. Historically, there have been insufficient data to support antenatal corticosteroids for women during the late preterm (LPT) period; however, results from a recent multicenter randomized control trial (RCT) found antenatal betamethasone decreased respiratory morbidity in LPT infants (Gyamfi-Bannerman et al., 2016).


The Antenatal Late Preterm Steroids study was a double-blind, placebo-controlled RCT conducted at 17 sites in the United States from 2010 to 2015 (Gyamfi-Bannerman et al., 2016). Participants were 2,831 women with a singleton pregnancy at 34.0 to 36.5 weeks' gestation with a planned birth or at high risk for birth during the LPT period (up to 36.6 weeks). Women were randomized to two injections of betamethasone or a placebo injection 24 hours apart. The primary outcome was a composite reflecting need for respiratory support within 72 hours of birth. Infants born to women in the betamethasone group had a decrease in the primary outcome compared to the placebo group (11.6% vs. 14.4%, P = .02) and had less-severe respiratory morbidity (8.1% vs. 12.1%, P < 0.001). Neonatal hypoglycemia (glucose < 40 mg/dL) occurred more frequently in the betamethasone group (24.0% vs. 15.0%), which may have implications for screening of babies exposed to betamethasone (Gyamfi-Bannerman et al.).


In March 2016, the Society for Maternal-Fetal Medicine (SMFM, 2016) issued a statement encouraging antenatal corticosteroid use for women at risk of LPT birth. Key points are summarized in Table 1. Because 70% of preterm births are LPT (Martin, Hamilton, Osterman, Curtin, & Matthews, 2015), these guidelines can protect LPT babies from respiratory morbidity and enhance perinatal safety and quality.

Table 1 - Click to enlarge in new windowTable 1. Summary of Recommendations From



Gyamfi-Bannerman C., Thom E. A., Blackwell S. C., Tita A. T., Reddy U. M., Saade G. R., ..., Jain L. (2016). Antenatal betamethasone for women at risk for late preterm delivery. The New England Journal of Medicine, 374(14), 1311-1320. doi:10.1056/NEJMoa1516783 [Context Link]


Martin J. A., Hamilton B. E., Osterman M. J., Curtin S. C., Matthews T. J. (2015). Births: Final data for 2013. National Vital Statistics Reports, 64(1), 1-65. [Context Link]


Society for Maternal-Fetal Medicine. (2016). Implementation of the use of antenatal corticosteroids in the late preterm birth period in women at risk for preterm delivery. American Journal of Obstetrics and Gynecology. doi:10.1016/j.ajog.2016.03.013. [Epub ahead of print] [Context Link]