Antenatal Corticosteroid Prophylaxis at Late Preterm Gestation: Clinical Guidelines Versus Clinical Practice

Abstract

Objective: We investigated how the Antenatal Late Preterm Steroids (ALPS) trial findings have been translated into clinical practice in Canada and the United States (U.S.).

Methods: The study included all live births in Nova Scotia, Canada, and the U.S. from 2007 to 2020. Antenatal corticosteroids (ACS) administration within specific categories of gestational age was assessed by calculating rates per 100 live births, and temporal changes were quantified using odds ratio (OR) and 95% confidence intervals (CI). Temporal trends in optimal and suboptimal ACS use were also assessed.

Results: In Nova Scotia, the rate of any ACS administration increased significantly among women delivering at 35⁰ to 36⁶ weeks, from 15.2% in 2007-2016 to 19.6% in 2017-2020 (OR 1.36, 95% CI 1.14-1.62). Overall, the U.S. rates were lower than the rates in Nova Scotia. In the U.S., rates of any ACS administration increased significantly across all gestational age categories: among live births at 35⁰ to 36⁶ weeks gestation, any ACS use increased from 4.1% in 2007-2016 to 18.5% in 2017-2020 (OR 5.33, 95% CI 5.28-5.38). Among infants between 24⁰ and 34⁶ weeks gestation in Nova Scotia, 32% received optimally timed ACS, while 47% received ACS with suboptimal timing. Of the women who received ACS in 2020, 34% in Canada and 20% in the U.S. delivered at ≥37 weeks.

Conclusion: Publication of the ALPS trial resulted in increased ACS administration at late preterm gestation in Nova Scotia, Canada, and the U.S. However, a significant fraction of women receiving ACS prophylaxis delivered at term gestation.

Keywords: Antenatal Late Preterm Steroids; antenatal corticosteroid; preterm birth.