1 Neonatal Intensive Care Unit, "Bambino Gesù" Children's Hospital IRCCS, Rome, Italy.
2 Neonatal and Pediatric Unit, Polo Ospedaliero Oltrepò, ASST Pavia, Pavia, Italy.
3 Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties "G. D'Alessandro", University of Palermo, Palermo, Italy.