1. Department of Gynecology Kurashiki Heisei Hospital Okayama Japan
2. Department of Gynecological Oncology Kawasaki Medical School Okayama Japan
3. Department of Obstetrics and Gynecology Tokyo Rosai Hospital, Japan Labour Health and Safety Organization Tokyo Japan
4. Department of Orthopaedic Surgery, Graduate School of Medicine Chiba University Chiba Japan
5. Department of Obstetrics and Gynecology 2 Kawasaki Medical School Okayama Japan