M Tahara1, D Tachibana2, A Hamuro1, T Misugi1, A Nakano1, M Koyama1. 1. Department of Obstetrics and Gynecology, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi Abeno-ku, Osaka, Osaka, 545-8585, Japan. 2. Department of Obstetrics and Gynecology, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi Abeno-ku, Osaka, Osaka, 545-8585, Japan. dtachibana@med.osaka-cu.ac.jp.