1. Visiting Researcher, Department of the Japan Obstetric Compensation System for Cerebral Palsy in Public Interest Incorporated Foundation, Japan Council for Quality Health Care, Tokyo, Japan;
2. Department of Obstetrics and Gynecology, St Marianna University School of Medicine, Kanagawa, Japan;
3. The Prevention Recurrence Committee, Mie Japan Obstetric Compensation System for Cerebral Palsy, Japan;
4. Department of Obstetrics and Gynecology, Mie University Graduate School of Medicine, Mie, Japan;
5. Department of Public Health, The University of Tokyo, Tokyo, Japan;
6. Department of the Japan Obstetric Compensation System for Cerebral Palsy in Public Interest Incorporated Foundation, Japan Council for Quality Health Care, Tokyo, Japan;
7. Maternal and Perinatal Care Center, Oita Prefectural Hospital, Oita, Japan;
8. Department of Obstetrics and Gynecology, Showa University Northern Yokohama Hospital, Kanagawa, Japan;
9. Department of Health Services Research, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan;
10. Department of Obstetrics and Gynecology, Nippon Medical School, Tokyo, Japan;
11. Department of Obstetrics and Gynecology, Fukushima Medical University, Fukushima, Japan;
12. Maeda Clinic, Incorporated Association Anzu-kai, Shizuoka, Japan;
13. Department of Obstetrics and Gynecology, Juntendo University Faculty of Medicine, Tokyo, Japan;
14. Kugayama Hospital, Tokyo, Japan;
15. Miyazaki University, Miyazaki, Japan