1. Department of Neonatology, Hospital Universitari i Politècnic La Fe, 106 Fernando Abril Martorell Avenue, 46026 Valencia, Spain
2. Department of Neonatology, Hospital Gregorio Marañón, 28009 Madrid, Spain
3. Division of Neonatology, Pediatric Department, Complexo Hospitalario Universitario de A Coruña (CHUAC), Sergas, 15006 A Coruña, Spain