Progress of induced labor in trial of labor after cesarean delivery

Objective The purpose of this study was to compare the first stage of labor progress in women who undergo an induction of labor after cesarean delivery with women who have spontaneous labor after cesarean delivery. Study Design We conducted a retrospective cohort study of consecutive women who had been admitted for delivery with a vertex-presenting fetus who achieved vaginal delivery after cesarean delivery. We compared women who underwent an induction of labor after cesarean delivery with women with spontaneous labor after cesarean delivery. Labor curves were constructed with a repeated-measures analysis; interval-censored regression was used to estimate the median time spent to dilate 1 cm, stratified by induction status, and adjusted by obesity, macrosomia, epidural, and previous vaginal delivery. Results Of 473 laboring women with a previous cesarean delivery, 234 women (49%) were induced. After adjustment for obesity, macrosomia, epidural, and previous vaginal delivery, women who underwent an induction had significantly longer labors than those women who experienced spontaneous labor. The median time to dilate from 4-10 cm took 5.6 hours (95% confidence interval, 1.8-18.0 hours) in the induction group and 3.2 hours (95% confidence interval, 1.0-10.3 hours) in the spontaneous labor group (P <.01). The time to progress 1 cm in dilation from 3-7 cm was different; however, after 7 cm, the time to progress 1 cm was not statistically different. Conclusion Women who undergo an induction of labor after cesarean delivery have a longer latent labor phase, but a similar active phase than those women who experience spontaneous labor. When making the diagnosis of labor dystocia for women who undergo an induction of labor after cesarean delivery, clinicians should use the same normative standards for labor treatment of women without a previous cesarean delivery as has been shown in previous work.