1. Department of Neonatology-Pediatrics, Hospital Universitari Dexeus, Barcelona, Spain;
2. Department of Neonatology, Hospital Clinic de Barcelona, Barcelona, Spain;
3. Health Sciences Research Institute (IUNICS), Palma de Mallorca, Spain;
4. Hospital de la Santa Creu i Sant Pau, Barcelona, Spain;
5. Department of Neonatology-Pediatrics, Hospital de Terrassa, Terrassa, Spain;
6. IDIBAPS – Hospital Clinic Barcelona, Barcelona, Spain