[1] Univ Fukui, Fac Med Sci, Dept Obstet & Gynecol, 23-3 Matsuoka Shimoaizuki, Eiheiji, Fukui 9101193, Japan
[2] Nara Prefecture Seiwa Med Ctr, Dept Obstet & Gynecol, Nara, Japan
[3] Tottori Univ, Dept Obstet & Gynecol, Sch Med, Tottori, Japan
[4] Hirosaki Univ, Dept Obstet & Gynecol, Grad Sch Med, Aomori, Japan
[5] Kindai Univ, Fac Med, Dept Med Oncol, Osaka, Japan
[6] Nagoya Univ, Dept Obstet & Gynecol, Grad Sch Med, Nagoya, Aichi, Japan
[7] Tokyo Med Univ, Dept Obstet & Gynecol, Ibaraki Med Ctr, Ibaraki, Japan
[8] Univ Ryukyus, Grad Sch Med, Dept Obstet & Gynecol, Nishihara, Okinawa, Japan