1 Section of Neonatology, Department of Pediatrics, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, Colorado.
2 Division of Neonatology, Department of Women's and Children's Health, University of Leipzig Medical Center, Leipzig, Germany.
3 Department of Pediatrics, University Hospital of Würzburg, Würzburg, Germany.
4 Medical Sciences, Division, Nuffield Department of Population Health, University of Oxford, National Perinatal Epidemiology Unit, Oxford, Oxfordshire, United Kingdom.