Labor progress among women attempting a trial of labor after cesarean. Do they have their own rules?

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.