Department of Obstetrics and Gynecology, Jichi Medical University School of Medicine, Tochigi, Japan

Akihide Ohkuchi, Hirotada Suzuki & Shigeki Matsubara

Department of Regional Pediatrics and Perinatology, Ehime University Graduate School of Medicine, Ehime, Japan

Keiichi Matsubara

Department of Obstetrics and Gynecology, Aichi Medical University School of Medicine, Aichi, Japan

Kazushi Watanabe & Takuya Saitou

Department of Obstetrics and Gynecology, Eiju General Hospital, Tokyo, Japan

Hideyuki Oda

Perinatal Center for Maternity and Neonates, Yokohama City University Medical Center, Kanagawa, Japan

Soichiro Obata

Department of Obstetrics and Gynecology, Yokohama Municipal Citizen’s Hospital, Kanagawa, Japan

Shinya Kondo

Department of Obstetrics and Gynecology, National Hospital Organization Iwakuni Clinical Center, Yamaguchi, Japan

Kiyoshi Noda

Department of Obstetrics and Gynecology, Japanese Red Cross Kumamoto Hospital, Kumamoto, Japan

Junya Miyoshi

Department of Obstetrics and Gynecology, Keio University School of Medicine, Tokyo, Japan

Satoru Ikenoue

Department of Obstetrics and Gynecology, National Hospital Organization, Saga National Hospital, Saga, Japan

Makoto Nomiyama

Department of Obstetrics and Gynecology, Saitama Medical Center, Saitama Medical University, Saitama, Japan

Hiroyuki Seki & Sachi Sukegawa

Department of Obstetrics and Gynecology, Matsunami General Hospital, Gifu, Japan

Satoshi Ichigo

Department of Obstetrics and Gynecology, Shinshu University School of Medicine, Nagano, Japan

Hirofumi Ando & Chiho Fuseya

Department of Obstetrics and Gynecology, St. Mary’s Hospital, Fukuoka, Japan

Takuya Shimomura

Department of Obstetrics and Gynecology, Ohara General Hospital, Fukushima, Japan

Rika Suzuki

Department of Obstetrics and Gynecology, Osaka University Graduate School of Medicine, Osaka, Japan

Kazuya Mimura

Department of Obstetrics and Gynecology, NHO Nagasaki Medical Center, Nagasaki, Japan

Ichiro Yasuhi & Masashi Fukuda

Department of Obstetrics and Gynecology, Tokyo Adventist Hospital, Tokyo, Japan

Sumiko Hara

Department of Obstetrics and Gynecology, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan

Ryuhei Kurashina

Department of Obstetrics and Gynecology, University of Toyama, Toyama, Japan

Arihiro Shiozaki & Shigeru Saito