1. Neonatal Intensive Care Unit, “Agios Panteleimon” General Hospital of Nikea, 3 D.Mantouvalou Str., Nikea, 18454 Piraeus, Greece
2. Neonatal Department, School of Medicine, National and Kapodistrian University of Athens, Aretaieio Hospital, 11528 Athens, Greece
3. Neonatal Intensive Care Unit, “Elena Venizelou” Maternity Hospital, 11521 Athens, Greece
4. Neonatal Intensive Care Unit, School of Medicine, University of Ioannina, 45110 Ioannina, Greece
5. Endocrinology Unit, 2nd Department of Obstetrics and Gynecology, School of Medicine, National and Kapodistrian University of Athens, Aretaieio Hospital, 11528 Athens, Greece