Objective: To examine the impact of Antenatal and Neonatal Guidelines, Education and Learning Systems (ANGELS) on neonatal intensive care unit (NICU) preterm delivery rates. Study design: In this longitudinal observational study, linked vital records and Medicaid claims records for 29,124 preterm births (April 2001–December 2012) to Medicaid covered women were used to examine factors predicting whether deliveries occurred at hospitals with neonatology-staffed NICUs. The factors associated with delivery are estimated and compared for baseline and three post-implementation periods. Results: Rates for NICU preterm deliveries increased from 28 to 37% over the time period. Compared to baseline, adjusted NICU delivery rates in the middle and late implementation periods were statistically significant (p < 0.001). Negative impacts of long travel times were reduced, while impacts of obstetrician prenatal care changed from negative to positive association. Conclusion: Findings validate the ANGELS initiative premise: academic specialists, working with community-based care providers, can improve perinatal regionalization.