1. Maternal and Child Health Bureau, Health Resources and Services Administration Department of Health and Human Services, Rockville, Maryland
2. Division of Reproductive Health, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention Department of Health and Human Services, Atlanta, Georgia
3. Commissioned Corps Public Health Service Department of Health and Human Services, Rockville, Maryland
4. Center for Financing, Access and Cost Trends, Agency for Healthcare Research and Quality Department of Health and Human Services, Rockville, Maryland
5. West Virginia University, School of Public Health, Morgantown
6. formerly with the Center for Financing, Access and Cost Trends, Agency for Healthcare Research and Quality Department of Health and Human Services, Rockville, Maryland at the time of analysis
7. Department of Pediatrics, Vanderbilt Center for Child Health Policy, Nashville, Tennessee
8. Department of Health Policy, Vanderbilt Center for Child Health Policy, Nashville, Tennessee
9. Division of Neonatology, Vanderbilt University Medical Center, Nashville, Tennessee