Abstract
Survival outcomes for infants born at 22-23 weeks' gestation vary widely across neonatal units. This national, prospective cohort study evaluated 919 infants born at 22-23 weeks' gestation in South Korea between 2013 and 2022, using Korean Neonatal Network data. Infants were categorized based on the level of neonatal care: 785 in lower-level centers (Group A) and 134 in higher-level centers (Group B). Survival was significantly higher in Group B (64.9%) compared to Group A (29.3%) (P < 0.0001). Early deaths occurred more frequently and earlier in Group A. Proactive care-including antenatal corticosteroids, antenatal antibiotics, and immediate surfactant administration-was more common in Group B. Antenatal corticosteroid was significantly associated with reduced risk of death (hazard ratio 0.58; 95% confidence interval, 0.49-0.69; P < 0.0001). The timing of rapid decline in survival was delayed in higher-level centers. In addition, classifying institutions into higher- and lower-level groups according to the survival of infants born at 22-23 weeks' gestation (≥50% vs. <50%) provides a good reflection of the quality of neonatal care. These findings highlight the importance of proactive care and timely in utero transfer to higher-level units in improving survival for peri-viable infants.