OBJECTIVE: To examine the pattern of labor progression among second parous women who had a vaginal birth after a cesarean (VBAC) compared with primiparous and multiparous women who delivered vaginally. DESIGN: Case-control study. SETTING: University hospital in Israel, August 2005 through November 2008. POPULATION: The cases were all 137 second parous women who had a VBAC during the study period. The control groups were: (1) 136 primiparous women; and (2) 137 women who had a second repeated vaginal delivery. METHODS: Data were extracted from the electronic medical records at admission, labor charts and medical records at discharge. Controls were frequency-matched to the study group for maternal age, gestational age and the work shift during which the delivery occurred. MAIN OUTCOME MEASURES: Length of the active phase of labor. Secondary outcomes were length of the second stage and incidence of vacuum extraction deliveries. Results. The length of the active phase was 176 +/- 116, 207 +/- 121 and 110 +/- 66 minutes in the study, first and second control groups, respectively. The active phase and stage 2 of the study group were significantly shorter than in the first control group (p=0.02 and p=0.007, respectively) and longer than in the second control group (p=0.001 in both stages). The incidence of vacuum deliveries was higher (p=0.001) in the study group (13.9%) compared with the second control group (1.5%). CONCLUSIONS: The results suggest that the pattern of labor progression among second parous women undergoing a trial of labor after cesarean differs from second parous women undergoing a repeated vaginal delivery. Recognizing this dissimilarity may help in avoiding unnecessary, occasionally deleterious, interventions.
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