FUJIBE Yuya^{1, 2}, MIZUOCHI Masahito², SHIMADA Hiroshi³, MARIYA Tasuku², NORO Kaoru^{1, 2}, YAMANAKA Ikuhito¹, TERAMOTO Mizue^{1, 2}, BABA Tsuyoshi², ISHIOKA Shinichi², SAITO Tsuyoshi² (1.Dept. of Obstetrics, NTT East Japan Sapporo Hospital, 2.Dept. of Obstetrics, Sapporo Medical University Hospital, 3.Dept. of Obstetrics, Nikko Memorial Hospital)

HORINOUCHI Takashi, YOSHIZATO Toshiyuki, INOUE Asami, KOUZUMA Yutaka, SHINAGAWA Takaaki, YOKOMINE Masato, USHIJIMA Kimio (Obstetrics and Gynecology, Kurume University Hospital)

INOUE Asami, HORINOUCHI Takashi, YOSHIZATO Toshiyuki, KOUZUMA Yutaka, SHINAGAWA Takaaki, YOKOMINE Masato, USHIJIMA Kimio (Obstetrics and Gynecology, Kurume University Hospital)

YAMAMOTO Kenta, MORI Ayumi, TENKUMO Chiaki, MORI Nobuhiro, HANAOKA Uiko, KANENISHI Kenji, TANAKA Hirokazu, HATA Toshiyuki (Faculty of Medicine, Kagawa University)

OKUYAMA Ayumi, DOHI Satoshi, SEO Kohei, ICHIZUKA Kiyotake, NAGATSUKA Masaaki (Obstetrics and Gynecology, Showa University Northern Yokohama Hospital)

MATSUMOTO Ryo, SUGIHARA Mika, ISHIDA Tsuyoshi, MURATA Takuya, NAKAI Yuichiro (Obstetrics and Gynecology, Kawasaki Medical School Hospital)