1. Department of Obstetrics and Gynecology; Yamaguchi University Graduate School of Medicine; Ube Japan
2. Department of Obstetrics and Gynecology; Gunma University Graduate School of Medicine; Maebashi Japan
3. Department of Obstetrics and Gynecology; Juntendo University School of Medicine; Tokyo Japan
4. Department of Obstetrics and Gynecology; Yokohama City University Hospital; Yokohama Japan
5. Saint Mother Obstetrics and Gynecology Clinic; Institute for ART; Fukuoka Japan
6. Department of Obstetrics and Gynecology; Shiga University of Medical Science; Otsu Japan