Background: 
            To evaluate the impact of ACS administration prior to delivery on neonatal outcomes
            in extreme preterm neonates delivered between 21 and 23 weeks of gestation. 
            Study Design: 
            This retrospective cohort study used data from the National Center for Health Statistics
            Vital Statistics database. Linked birth and infant death data files from 2015 to 2021
            were included in the analysis. The study included singleton, non-anomalous pregnancies
            that were delivered between 21 weeks and 24 weeks gestation. Analysis was limited
            to birth with known ACS status. The outcomes of interest were infant mortality, 5-minute
            Apgar score <6, and NICU admission. Univariate analysis was performed to determine
            the association between exposure and outcome. Logistic regression analysis was performed
            to determine the association adjusting for potential confounders. 
            Results: 
            There were 50,671 births included in the analysis. In this group, 15,601 (31%) received
            ACS prior to delivery. ACS administration prior to delivery was associated with lower
            neonatal death rate between 21 – 24 weeks (32.9% vs 56.1%, p<0.0001, aOR 0.53 [0.51
            – 0.56]). Sub-analysis based on delivery at each gestational week demonstrated a protective
            effect at 21 weeks (70.1% vs 80.7%, p=0.001, aOR: 0.56 [0.34 – 0.91]); at 22 weeks
            (54.1% vs 75.9%, aOR: 0.40 [0.35 – 0.47]); at 23 weeks (39.1% vs 50.9%, aOR: 0.65,
            aOR [0.61 – 0.70]); and at 24 weeks (24.6% vs 30.1%, aOR: 0.78 [0.73 – 0.83]).
            Conclusions:
            Antenatal corticosteroid administration in extreme preterm neonates born between 21
            and 24 weeks was associated with improved survival.