The Influence of Continuous Epidural Bupivacaine Analgesia on the Second Stage of Labor and Method of Delivery in Nulliparous Women

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Abstract
A randomized, double blind, placebo-controlled study was performed to evaluate the analgesic efficacy and influence of continuing an epidural infusion of 0.125% bupivacaine beyond a cervical dilatation of 8 cm in nulliparous women. When the cervix was .gtoreq. 8 cm dilated, coded study solution was substituted for the known 0.125% bupivacaine solution. The study solution for 46 patients was 0.125% bupivacaine; 46 patients received saline. During the first stage of labor, 44 (96%) women in the bupivacaine group, and 45 (98%) in the saline group, had analgesia of excellent or good quality. During the second stage, 36 (82%) women in the bupivacaine group, versus 18 (41%) women in the saline group, had analgesia of excellent or good quality (P < .0001). Six (13%) women in each group underwent cesarean delivery after the start of the study solution. Among the women who delivered vaginally, the mean (.+-. S.D.) duration of the second stage of labor was 124 (.+-. 70) min in the bupivacaine group, versus 94 (.+-.54) min in the saline group (P < .05). Twenty-one of 40 (53%) women in the bupivacaine group, versus 11 of 40 (28%) in the saline group, underwent instrumental vaginal delivery (P < .05). Twenty-eight of 40 (70%) women in the bupivacaine group, versus six of 40 (15%) in the saline group, had surgical perineal anesthesia for vaginal delivery (P < .0001). There were no significant differences between groups in Apgar scores or umbilical cord blood acid-base values. We conclude that, under the conditions of the present study, epidural bupivacaine infusion beyond a cervical dilatation of 8 cm provided satisfactory analgesia, but prolonged the second stage of labor and increased the frequency of instrumental delivery in nulliparous women. However, maintenance of epidural bupivacaine analgesia did not result in an increased incidence of abnormal position of the vertex or a more frequent performance of cesarean section.