RESUMO
BACKGROUND: The supply of US neonatal intensive care unit (NICU) beds and neonatologists is known to vary markedly across regions, but there have been no investigation of patterns of recent growth (1991-2017) in NICUs in relation to newborn need. OBJECTIVE: The objective of this study was to test the hypothesis that greater growth in NICU capacity occurred in neonatal intensive care regions with higher perinatal risk. RESEARCH DESIGN: A longitudinal ecological analysis with neonatal intensive care regions (n=246) as the units of analysis. Associations were tested using linear regression. SUBJECTS: All US live births ≥400 g in 1991 (n=4,103,528) and 2017 (n=3,849,644). MEASURES: Primary measures of risk were the proportions of low-birth weight and very low-birth weight newborns and mothers who were Black or had low educational attainment. RESULTS: Over 26 years, the numbers of NICU beds and neonatologists per live birth increased 42% and 200%, respectively, with marked variation in growth across regions (interquartile range: 0.3-4.1, beds; neonatologists, 0.4-1.0 per 1000 live births). A weak association of capacity with perinatal risk in 1991 was absent in 2017. There was no meaningful (ie, clinical or policy relevant) association between regional changes in capacity and regions with higher perinatal risk or lower capacity in 1991; higher increases in perinatal risk were not associated with higher capacity growth. CONCLUSION: The lack of association between newborn medical needs and the supply of NICU resources raises questions about the current effectiveness of newborn care at a population level.