^○Yuriko Noma, Tsutomu Ida, Risa Takeuchi, Satoko Yoshihara, Daichi Kurihara, Midori Saito, Yayoiko Koizumi, Yusuke Kohri, Yuri Tachibana, Yuko Ooyoshi, Ichiro Ono, Keijiro Sumori (Department of Obstetrics and Gynecology, Ome Municipal General Hospital, Japan)

^○Kayo Asada, Rino Shoji, Minori Kasuya, Aeri Aotsuka, Masao Nakabayashi, Minoru Nakabayashi (Department of obstetrics and Gynecology, Sanraku Hospital, Tokyo, Japan)

^○Masashi Nishimoto, Yoko Yano, Takahiro Kaji, Keitaro Yamanaka, Maho Azumi, Keiichi Washio, Yuki Sasagawa, Satoshi Nagamata, Yumika Yamano, Yui Yamasaki, Yoshito Terai (Obstetrics and gynecology, Kobe University, Japan)

^○Kenichi Yoshikawa, Fusanri Yotsumoto, Kouichirou Shigekawa, Chihiro Kiyoshima, Yukiko Noguchi, Tomohiro Ito, Daisuke Miyahara, Shingo Miyamoto (Department of Obstetrics and gynecology, Fukuoka University Hospital, Japan)

^○Michio Sanada, Shinsuke Hanawa, Shirou Satou, Noriko Nishikata, Shintarou Obata (Department of Obstetrics & Gynecology, Narita Red Cross hospital, Chiba, Japan)