Objective: To investigate whether the Antenatal Late Preterm Steroids (ALPS) trial, has been translated into clinical practice in Canada and the United States. Temporal trends in optimal and suboptimal antenatal corticosteroid (ACS) use among late preterm deliveries were also assessed. Design: A retrospective cohort study. Setting: USA and Canada, 2007 to 2020. Population: All live births in the US (n= 32,476,039) and Nova Scotia, Canada (n= 116,575). Methods and Main outcome measured: Using data from the Natality database and the Nova Scotia Atlee Perinatal Database, ACS administration within specific categories of gestational age was assessed by calculating rates per 100 live births. 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 35-36 weeks, from 15.2% in 2007-2016 to 19.6% in 2017-2020 (OR 1.36, 95%CI 1.14, 1.62). In the U.S., among live births at 35-36 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 24 and 34 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 United States 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.