1. Division of Obstetrics and Gynecology; Kanagawa Children's Medical Center; Yokohama Kanagawa Japan
2. Department of Obstetrics and Gynecology; Yokohama City University; Yokohama Kanagawa Japan
3. Division of Neonatology; Kanagawa Children's Medical Center; Yokohama Kanagawa Japan
4. Division of Pediatrics; Saitama Citizens Medical Center; Saitama Saitama Japan
5. Division of Medical Genetics; Kanagawa Children's Medical Center; Yokohama Kanagawa Japan
6. Department of Integrated Women's Health; St. Luke's International Hospital; Chuo-ku Tokyo Japan