Labor Patterns In Women Undergoing Vaginal Birth After Cesarean Delivery

Objective: To describe labor patterns in women undergoing vaginal birth after cesarean(VBAC)and to examine whether the labor pattern differed according to whether the previous cesarean was performed electively or after a trial of labor.Methods: In a retrospective observational study at Shengjing Hospital from January2015 to July 2017,we compared the labor duration of latent,active phase and second stage among 50 women undergoing VBAC with 51 nulliparous women and 51 multiparous women.According to whether they had an elective cesarean(20)or a cesarean after a trial of labor(27)(data of 3 women was not available)in the previous pregnancy,we divided the VBAC women into two groups and compared the labor durations.Results: There was no significant difference in median labor duration of latent phase between the groups(p>0.05).The median length of the active phase was 140,170,80 minutes in the VBAC,nulliparous and multiparous groups,respectively.The active phase were significantly longer than in the multiparous(p<0.001),but no significant difference compared to nulliparous(p=0.495).The median length of second stage for VBAC was 23 minutes which was significantly shorter than nulliparous(38 minutes,p<0.001)and longer than multiparous(80 minutes,p<0.001).Between subgroups within the VBAC according to whether they had an elective cesarean or a cesarean after a trial of labor in the previous pregnancy,there were no significant differences in the median labor duration of each stage.Conclusion: The labor patterns of first stage in women undergoing VBAC was similar to nulliparous and progress slower than multiparous,regardless of the indication for the previous cesarean,and labor curve describes a gradual smooth transition.Recognizing this dissimilarity may help in avoiding unnecessary,occasionally deleterious,interventions.And should cautious about labor arrest to prevent uterine rupture.The shorter second stage of labor for VBAC compared to nulliparous could be a further factor increasing the motivation for a trial of labor after cesarean(TOLAC).Obstetrician may use this information in antenatal and intrapartum counselling.