1. Department of Gynecology; Yokohama City University, Medical Center; 4-57 Urafune-cho, Minami 232-0024 Yokohama Kanagawa Japan
2. Department of Obstetrics and Gynecology; Yokohama City University, School of Medicine; 3-9 Fukuura, Kanazawa 236-0004 Yokohama Kanagawa Japan
3. Ebina Ladies Clinic; 3-3-1 Chuo 243-0432 Ebina Kanagawa Japan