^○Yuko Matsuda, Kanako Murata, Mariko Nakahara, Fuyuko Nagai, Yasuka Miyakuni, Kentaro Miyai (Tobu Chiiki Hospital, Tokyo, Japan)

^○Yasuyo Maruyama, Go Hirata, Naoki Tsuchiya, Yui Noguchi, Ryoko Kajiyama, Tamina Kino, Misaki Toda, Yuko Mine, Yuki Ogawara, Yuki Naruke, Tomoo Hirabuki (Department of Cardiovascular Surgery, Odawara Municipal Hospital, Kanagawa, Japan)

^○Go Ichikawa, Shi Honglian, Ayako Takizawa, Asako Nagashima, Mayu Yamada, Eika Harigane, Asako Watanabe, Yohei Tsunoda, Hiroki Shinmura, Ryuhei Kurashina, Hanako Kaseki, Masao Ichikawa, Takashi Matsushima, Shigeo Akira, Shunji Suzuki (Division of Obstetrics and Gynecology, Nippon Medical School, Japan)

^○Utako Fujii, Sawako Fujiwara, Yumi Sunohara, Hiroka Akita, Sayako Ikeda, Miho Sano, Shigehiko Morikawa (Department of Obstetrics and Gynecology, Komaki City Hospital, Aichi, Japan)

^○Tomoaki Fukagawa, Kazuho Nakanishi, Takakazu Ogawa, Yuri Maeoka, Yukari Ohishi, Yuki Kaito, Yuta Ueno, Momoko Ohwada, Yuko Murakawa, Takashi Yamada (Department of Obstetrics and Gynecology, Nippon Medical School Chiba hokusoh hospital, Chiba, Japan)

^○Rie Minami, Masumi Honda, Masako Nakajima, Tae Kusabiraki, Shinichi Yoshikoshi, Yuka Ametani, Satoshi Tanimura (Toyama Prefectural Central Hospital, Japan)