1. Department of Obstetrics and Gynecology, Juntendo University Faculty of Medicine
2. Department of Obstetrics and Gynecology, Urayasu Hospital, Juntendo University
3. Department of Obstetrics and Gynecology, Sanno Hospital
4. Department of Obstetrics and Gynecology, The University of Tokyo
5. Department of Gynecology and Obstetrics, Kyoto University