(414) County-level antenatal steroid exposure among late preterm births, 2016-2021

To examine the pace of adoption of new evidence demonstrating the benefits of antenatal steroids among late preterm births throughout the United States.

Study Design:

This is a cross-sectional analysis using the late preterm births between 2016 and 2021 using US natality data. County-level proportions of late preterm births exposed to antenatal steroids were calculated by year for counties and reported at least one steroid exposed infant per year. Ridgeline plots, weighted by a county’s annual late preterm birth delivery volume, were constructed to demonstrate if and how the county-level proportions changed by year. Yearly county proportions of late preterm births exposed to steroids were compared using nonparametric K-sample test on the equality of medians.

Results:

There were 995 counties, and 1,338,973 late preterm births were included in this analysis. Figure 1 shows the proportion of late preterm births exposed to steroids increased significantly in US counties between 2016 and 2021 and the interquartile range widened: median (IQR) 7.1% (3.7-12.5%) to 15.4% (7.7-24.4%), p< 0.001. There was no significant difference in the medians between 2020 and 2021.

Conclusion: The proportion of late preterm births exposed to steroids increased significantly among US counties after the publication of the ALPS Trial, though practice variation widened over time. The observed increase in county-level proportions of steroid-exposed late preterm births plateaued in 2020, suggesting the practice change observed after the ALPS Trial may have reached a steady state. Studies examining the drivers of the wide variation in steroid exposure, including hospital, clinician, and patient factors, should be conducted to identify both barriers and facilitators to the adoption of this evidence-based recommendation.