1. Osaka University Faculty of Medicine, Suita, Osaka, Japan
2. Department of Obstetrics and Gynecology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
3. Shiga University of Medical Science, Otsu, Shiga, Japan
4. Tottori University School of Medicine, Yonago, Tottori, Japan
5. Gunma University Faculty of Medicine, Maebashi, Gunma, Japan
6. Kumamoto University School of Medicine, Chuoku, Kumamoto, Japan
7. Hirosaki University Faculty of Medicine, Hirosaki, Aomori, Japan