title: Erratum to: The use of balloons for uterine cervical ripening is associated with an increased risk of umbilical cord prolapse: population based questionnaire survey in Japan.
authors.affiliation: Department of Obstetrics and Gynecology, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, 142-8666, Japan. hasejun@oak.dti.ne.jp.
authors.forename: Junichi
authors.initials: J
authors.lastname: Hasegawa
authors.affiliation: Department of Obstetrics and Gynecology, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, 142-8666, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Sekizawa
authors.affiliation: Department of Obstetrics and Gynecology, Mie University School of Medicine, Mie, Japan.
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Ikeda
authors.affiliation: Kawakita General Hospital, Tokyo, Japan.
authors.forename: Mitsuhiko
authors.initials: M
authors.lastname: Koresawa
authors.affiliation: Ishiwata Obstetrics and Gynecology Hospital, Ibaraki, Japan.
authors.forename: Isamu
authors.initials: I
authors.lastname: Ishiwata
authors.affiliation: Doai Memorial Hospital, Tokyo, Japan.
authors.forename: Masakiyo
authors.initials: M
authors.lastname: Kawabata
authors.affiliation: Seijo-Kinoshita Hospital, Tokyo, Japan.
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Kinoshita