1. Medical Park Yokohama Yokohama Japan
2. Department of Integrated Women's Health St. Luke's International Hospital Tokyo Japan
3. Department of Obstetrics and Gynecology Juntendo University Urayasu Hospital Urayasu Japan
4. Medical Division Gunze Limited Tokyo Japan
5. Department of Obstetrics and Gynecology University of Tokyo Tokyo Japan
6. Department of Obstetrics and Gynecology Toho University Omori Medical Center Tokyo Japan