1. Department of Pediatrics, School of Medicine, Emory University, Children's Healthcare of Atlanta, Atlanta, Georgia;
2. Statistics and Epidemiology Unit, RTI International, Research Triangle Park, North Carolina;
3. Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa;
4. Department of Pediatrics, School of Medicine, Wayne State University, Detroit, Michigan;
5. Department of Pediatrics, Women and Infants' Hospital, Brown University, Providence, Rhode Island;
6. Department of Pediatrics, Rainbow Babies and Children's Hospital, Case Western Reserve University, Cleveland, Ohio;
7. Department of Pediatrics, School of Medicine, University of Cincinnati, Cincinnati, Ohio;
8. Division of Neonatology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama;
9. Department of Pediatrics, University of Texas Medical School at Houston, Houston, Texas;
10. Department of Pediatrics, School of Medicine, Indiana University, Indianapolis, Indiana;
11. Department of Neonatology, University of California, San Diego, Medical Center, San Diego, California;
12. Department of Pediatrics, School of Medicine, Yale University, New Haven, Connecticut;
13. Department of Pediatrics, Miller School of Medicine, University of Miami, Miami, Florida;
14. Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas;
15. Department of Pediatrics, School of Medicine, Wake Forest University, Winston-Salem, North Carolina;
16. Department of Pediatrics, School of Medicine, Duke University, Durham, North Carolina;
17. Department of Pediatrics, School of Medicine, Stanford University Palo Alto, California;
18. Division of Neonatology, Department of Pediatrics, School of Medicine, University of Utah, Salt Lake City, Utah;
19. Department of Pediatrics, School of Medicine and Dentistry, University of Rochester, Rochester, New York;
20. Division of Newborn Medicine, Department of Pediatrics, Floating Hospital for Children, Tufts Medical Center, Boston, Massachusetts;
21. Department of Pediatrics, University of New Mexico Health Sciences Center, Albuquerque, New Mexico;
22. Statistics and Epidemiology Unit, RTI International, Rockville, Maryland; and
23. Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health Bethesda, Maryland