Abstract
BACKGROUND: To clarify whether the use of balloons for cervical ripening is associated with the incidence of umbilical cord prolapse. METHODS: A postal questionnaire survey was distributed in Japan. Cases of umbilical cord prolapse occurring during labor in association with the use of balloons for cervical ripening between 2007 and 2011 in Japan were analyzed. RESULTS: Answers from 942 institutions were obtained. The subjects included 369 patients with fore-lying or prolapse of the umbilical cord among a total of 2,037,460 deliveries. Among the singleton vertex cases, fore-lying or prolapse of the umbilical cord during labor were observed in 88 (0.005%) of 1,891,189 deliveries not associated with the use of balloons for cervical ripening and in 93 (0.064%) of 146,271 deliveries associated with the use of balloons for cervical ripening (Odds ratio 13.67, 95% confidence interval 10.21, 18.30). All types of balloons were significantly associated with the occurrence of fore-lying or prolapse of the umbilical cord. A total of 39% of cases of umbilical cord prolapse occurred during manual or spontaneous balloon removal, while 53% of cases occurred after a while not directly associated with balloon removal. CONCLUSION: The risk of umbilical cord prolapse was significantly increased during the use of balloons for cervical ripening, especially in cases involving the use of disk-type and ball-type balloons filled with large amounts of water.