An evaluation of antenatal corticosteroid use and timing in a large US birth cohort 2017-2021

There is a lack of published data on the contemporary use and timing of antenatal corticosteroids in the United States. Our primary objective was to address this gap using clinical data from a large US birth cohort. Our secondary objective was to identify factors associated with optimally timed steroids in births <34 weeks' gestation.

This retrospective study included de-identified clinical data from a quality improvement database for births at 24⁺⁰-42⁺⁶ weeks' gestation between January 1, 2017 and December 31, 2021 at 12 hospitals in the northwest United States. We evaluated the proportion of live births <34 weeks' gestation that received at least a first dose of antenatal steroids within the 7 days preceding birth ("optimally timed" steroids), and the proportion of patients given antenatal steroids who delivered at term. Annual rates of these measures were also evaluated across the study period. Associations between optimal steroid timing in preterm births <34 weeks' gestation and sociodemographic and medical characteristics were explored with a multilevel logistic regression model using hospitals as random effects.

Of 105,981 patients included in the analysis, 6.1% (6443) received steroids before 37 weeks' gestation. A total of 83.1% of live births <34 weeks' gestation received antenatal steroids, but only 55.4% received optimally timed steroids. The rate of optimally timed steroids in births <34 weeks' gestation was stable between 2017 and 2021. Over the same period, the proportion of births at 34⁺⁰-36⁺⁶ weeks' gestation that received steroids increased from 36.6% to 46.6%, and the proportion that received steroids and then delivered at term increased from 15.5% to 22.1% (p < 0.001). After adjusting for confounders, preeclampsia was associated with increased odds for optimally timed steroids in births <34 weeks' gestation (OR 1.46; 95% CI 1.20, 1.79) while ruptured membranes (odds ratio [OR], 0.76; 95% CI, 0.63, 0.91) and placenta previa (OR, 0.28; 95% CI, 0.16, 0.51) were associated with decreased odds.

In our study, most patients who delivered at <34 weeks' gestation received at least one dose of antenatal corticosteroids, but this was outside of the optimal 7-day window in approximately half of cases. Quality improvement efforts should focus on timing, as well as the use of antenatal corticosteroids.