1. Department of Obstetrics and Gynecology Jichi Medical University School of Medicine Tochigi Japan
2. Department of Medical Informatics, Center for Information Jichi Medical University School of Medicine Tochigi Japan
3. Department of Obstetrics and Gynecology Jikei University School of Medicine Tokyo Japan
4. Department of Obstetrics and Gynecology University of Tokyo Hospital Tokyo Japan
5. Department of Obstetrics and Gynecology Tokyo Metropolitan Bokutoh Hospital Tokyo Japan
6. Department of Obstetrics and Gynecology Nippon Medical School Tama Nagayama Hospital Tokyo Japan
7. Department of Obstetrics and Gynecology, Graduate School of Medicine and Pharmaceutical Science for Research University of Toyama Toyama Japan
8. Department of Obstetrics and Gynecology Mishima General Hospital Shizuoka Japan