Abstract Objectives To evaluate trends in neonatal intensive care unit (NICU) admissions, illness acuity, and hospitalization costs among U.S. children’s hospitals from 2017 to 2022. Methods This retrospective cohort study used data from the Pediatric Health Information System (PHIS) and included all NICU admissions. We examined trends in patient characteristics (e.g., gestational age, complex chronic conditions), illness severity scores, and standardized hospital costs. Interrupted time series analyses assessed changes in NICU costs over time. Results There were 234,571 infants admitted to NICUs in US children’s hospitals between 2017 and 2022. NICU admissions shifted significantly by gestational age with admissions increasing by 10–18% among extremely, very, and late preterm infants. Term infants remained the largest admission group, averaging 45% annually ( p < 0.001). Infants with ≥1 complex chronic condition increased from 46.6% in 2017 to 50.9% in 2022 ( p < 0.001). NICU-specific illness severity increased modestly over time (1.14–1.24, p < 0.001). Median standardized NICU hospital costs rose by approximately 20% over the study period, with notable inflections in early 2020 and 2021. Conclusions Among US children’s hospitals in the PHIS database, NICU admissions were increasingly complex and costly. These findings highlight the importance of ongoing monitoring of resource use and patient mix in specialized NICU settings.
Vance et al. (2026) studied this question.