data are available only one to two years after the care was provided. Interpretation of the findings, of course, is limited to the particular population included in the cohort. Population-based studies also have some notable strengths. The analyses include the experience of all newborns in the birth cohort regardless of health status, the hospital where they received care, or whether they were admitted to a NICU. This is particularly important for less severely ill newborns (e.g., late preterm newborns) where the majority are not admitted to a NICU. Inclusion in the dataset is not dependent on the willingness of the hospital to participate. Newborns can be followed both at the hospital of birth and at any other hospitals to which they are transferred. Most importantly, newborn care and outcomes can be measured after they are discharged home. The cost and possible overuse of NICU care are growing concerns as the number of NICU beds expands. Population-based studies are often a better choice than member-based collaboratives to examine these issues which are important, but may impact hospitals’ revenue or reputations, particularly when coupled with public reporting. It should, however, be noted that some of the best documented efforts to remedy overuse in newborn care, such as the reduction of needless antibiotic use, have been done under the auspices of the VON and the CPQCC. A REPORT OF THE DARTMOUTH ATLAS PROJECT 3 Why examine several groups of newborns? Each of the cohorts is associated with different types of information. While none has complete information on both utilization of care and outcomes, together they provide a consistent set of findings: the care of newborns varies widely across regions and hospitals, even after adjusting for differences in health status. These findings raise troubling questions about whether newborns are receiving the care that they need and that their families want. Table 1.1. Study periods, number of live births, and number of regions included for each study population Years Total live births Number of regions Section 2 U.S. birth cohort 2013 3,940,764 246 Anthem BCBS 2010-2014 1,205,091 246 Commercial plans 698,865 Medicaid plans 506,226 Section 3 Texas Medicaid 2010-2014 1,133,441 21 Section 4 Norway 2009-2014 368,068 15 Note: The number of newborns and regions used for specific analyses may be lower. A Report of the Dartmouth Atlas Project 4 DARTMOUTH ATLAS OF NEONATAL INTENSIVE CARE Neonatal Intensive Care This report focuses particularly on neonatal intensive care, one of the most effective and expensive modalities of pediatric care. Since its origin in the 1960s, neonatal intensive care has developed into a mature and widely available clinical service while undergoing robust growth in the number of neonatal intensive care unit (NICU) beds and clinicians across the United States.2 Neonatal intensive care has greatly reduced newborn mortality and morbidity caused by prematurity, congenital anomalies, and other neonatal illnesses,3,4 but many aspects of quality, outcomes, and efficiency of care remain incompletely documented and poorly understood.5-12 As NICUs expand, analysis of the care provided has become more urgent. For very sick newborns, the benefits of NICUs clearly outweigh any risks. But those with less severe illnesses have less to gain from intensive care yet are still exposed to the possible adverse effects of a hospital setting designed primarily for critical care. Many NICUs are relatively bright and noisy, while newborn sleep patterns and neurodevelopment depend on quiet and dim lights, particularly at night. Despite the best efforts of doctors and nurses, interactions between the newborn and mother are often affected, impairing maternal-newborn bonding and breastfeeding, and potentially leading to disruptions in newborn development and the risk of depression for mothers.13-15 Hospital-acquired infections and antibiotic use are also more likely, as are more frequent blood and imaging tests.16-18 Neonatologists are increasingly concerned about balancing these potential harms of NICU environments against possible benefits for late preterm and mildly ill newborns. Identifying overuse could reveal opportunities to decrease adverse effects, reduce unnecessary spending, allow for earlier discharge home, and improve outcomes for newborns and their families. Concerns about the varying effectiveness of NICU care for different cohorts of newborns, including those at low risk for complications, are joined by questions about high expenditures. The care of extremely premature newborns is understandably expensive. Clinicians, economists, and ethicists have debated for three decades about the balance between costs and outcomes for these newborns’ care.19,20 Much less effort has been directed at measuring payments for low-risk newborns and understanding why expenditures for all newborns differ so much across hospitals.21 NICUs do not practice in isolation but are part of a wider system of reproductive health and perinatal care. Good birth outcomes are dependent on monitoring maternal and fetal risk (e.g., diabetes, hypertension, obesity, twins) during pregnancy and, when appropriate, referral to tertiary centers, including regional perinatal health centers staffed with maternal-fetal medicine physicians and other specialized