1. Saitama City Hospital Division of Neonatology, Department of Pediatrics, , Saitama, 336-8522, Japan
2. Keio University School of Medicine Department of Pediatrics, , Tokyo, 160-8582, Japan
3. Saitama Medical Center, Dokkyo Medical University Department of Pediatrics, , Saitama, 343-0845, Japan
4. Nihon University School of Medicine Department of Pediatrics and Child Health, , Tokyo, 173-8610, Japan