1. Division of Neonatology, Department of Pediatrics, Children’s Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania
2. Biostatistics and Epidemiology Division, RTI International, Research Triangle Park, North Carolina
3. Department of Pediatrics, Women and Infant’s Hospital of Rhode Island, Brown University, Providence, Rhode Island
4. Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
5. Perinatal Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio
6. Division of Neonatology, Department of Pediatrics, University of Texas Health Science Center at Houston, Houston, Texas; and
7. Division of Neonatology, University of Utah, Salt Lake City, Utah