1. Department of Obstetrics and Gynecology; Gifu University; Gifu Japan
2. Department of Obstetrics and Gynecology; Kurume University School of Medicine; Kurume Japan
3. Department of Obstetrics and Gynecology; Hyogo College of Medicine; Nishinomiya Japan
4. Department of Obstetrics and Gynecology; Tottori University School of Medicine; Yonago Japan
5. Department of Obstetrics and Gynecology; Nagoya City University, Graduate School of Medicine; Nagoya Japan
6. Department of Obstetrics and Gynecology; Oita University Faculty of Medicine; Yufu Japan
7. Department of Obstetrics and Gynecology; Kansai Rosai Hospital; Amagasaki Japan