1. İstanbul University Cerrahpaşa Faculty of Medicine, Department of Pediatric Endocrinology, İstanbul, Turkey

2. University of Health Science, Haseki Training and Research Hospital, Newborn Intensive Unit, İstanbul, Turkey

3. Şişli Hamidiye Etfal Training and Research Hospital, Newborn Intensive Unit, İstanbul, Turkey

4. University of Exeter Medical School, Institute of Biomedical and Clinical Science, Exeter, United Kingdom