Success in achieving vaginal delivery following a prior cesarean birth is believed to be related to the indication for the cesarean delivery. Shipp and colleagues studied more than 2,000 women during a trial of labor following cesarean delivery to determine the influence of the indication for the prior cesarean delivery and compare their rate of vaginal birth with that of nulliparous patients.

They studied the records of all women admitted to a teaching hospital between 1984 and 1996 for trial of labor following one cesarean delivery and the records of all nulliparous mothers delivering in the same hospital between December 1994 and August 1995. All of the mothers studied were in spontaneous labor at term with singleton pregnancies in cephalic presentations. The indications for the cesarean deliveries were categorized as breech presentation, failure to progress, non-reassuring fetal testing and other. Only the principal indication was used for each patient.

The nulliparous patients were significantly younger than those with prior cesarean deliveries (mean age: 28.2 years compared with 30.8 years, respectively) and a higher proportion of this group (16.1 percent) received public aid than of the cesarean group (14.3 percent). The cesarean delivery rate was 13.5 percent in nulliparas compared with 28.7 percent in the mothers with prior cesarean delivery. Mothers in the prior cesarean delivery group had infants with significantly higher mean birth weights (3,501 g [7 lb, 9 oz] compared with 3,423 g [7 lb, 8 oz]), and were more likely to receive epidural analgesia (71.6 compared with 67.0 percent), but less likely to receive oxytocin (48.2 compared with 54.9 percent) or to have ruptured membranes or cervical dilation of 4 cm or more on admission. After multiple logistic regression analysis to control for all important variables, women with prior cesarean deliveries were found to be 2.6 times more likely than nulliparous women to deliver by cesarean after trial of labor.

Analysis by indication for the prior cesarean delivery showed significant differences in the risk of repeat cesarean delivery. Mothers with a previous cesarean delivery related to breech presentation had a cesarean delivery rate of 13.9 percent, almost equivalent to the rate in nulliparous patients. If the prior cesarean was attributed to nonreassuring fetal testing or “other” indications, the rate of repeated cesarean delivery rose to about 25 percent. The highest rate of repeat cesarean delivery, 37.3 percent, was associated with a history of failure to progress during labor. Multiple logistic regression to control for several significant variables indicated that prior failure to progress was associated with a cesarean delivery rate four times that of the nulliparous group, and the rate in women with a previous cesarean related to nonreassuring fetal testing was twice that of the rate in the nulliparous group.

The authors conclude that the rate of cesarean delivery during trial of labor following prior cesarean delivery is strongly related to the indication for the initial cesarean. In advising mothers about vaginal delivery following cesarean birth, a history of failure to progress is particularly significant. Mothers with a history of breech delivery are just as likely as nulliparous patients to achieve vaginal delivery in subsequent pregnancies.