1. Section of Neonatology, Department of Pediatrics, School of Medicine, University of Colorado and Colorado School of Public Health, Aurora, Colorado;
2. Departments of Pediatrics and Obstetrics and Gynecology, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire;
3. Section of Neonatology, Department of Pediatrics, University of Calgary, Calgary, Alberta, Canada; and
4. Division of Neonatal and Perinatal Medicine, Saint Louis University, St Louis, Missouri