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

Affiliations

• ¹ Department of Obstetrics and Gynecology, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, 142-8666, Japan. [email protected].
• ² Department of Obstetrics and Gynecology, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, 142-8666, Japan.
• ³ Department of Obstetrics and Gynecology, Mie University School of Medicine, Mie, Japan.
• ⁴ Kawakita General Hospital, Tokyo, Japan.
• ⁵ Ishiwata Obstetrics and Gynecology Hospital, Ibaraki, Japan.
• ⁶ Doai Memorial Hospital, Tokyo, Japan.
• ⁷ Seijo-Kinoshita Hospital, Tokyo, Japan.