1. Department of Obstetrics and Gynecology, Faculty of Medicine Toho University Tokyo Japan
2. Department of Obstetrics and Gynecology Saitama Medical University Saitama Japan
3. Department of Obstetrics and Gynecology, Graduate School of Biomedical Sciences Tokushima University Tokushima Japan
4. Department of Obstetrics and Gynecology Tokyo Medical University Tokyo Japan
5. Kato Ladies Clinic Tokyo Japan
6. Department of Obstetrics and Gynecology The Jikei University School of Medicine Tokyo Japan
7. Department of Obstetrics and Gynecology Nippon Medical School Tokyo Japan
8. Department of Obstetrics and Gynecology, Graduate School of Medicine The University of Tokyo Tokyo Japan
9. Department of Obstetrics and Gynecology School of Medicine, Keio University Tokyo Japan