Cervical length measured before delivery and the success rate of vaginal birth after cesarean (VBAC)

Abstract

Objective: To test the hypothesis that measuring cervical length (CL) close to the time of delivery is a predictor of successful vaginal birth following a cesarean.

Methods: A prospective longitudinal study included women with singleton pregnancies at 38–41 weeks, who previously underwent a cesarean, and who were interested in trial of labor. Patients who did not have a spontaneous onset of labor were induced at 41 weeks’ gestation. CL measurements were performed prior to labor by transvaginal ultrasound, recorded, and blinded from the caring physicians.

Results: Vaginal birth was achieved in 63/105 (60%) of patients participating in the study. The mode of delivery significantly correlated with CL, Bishop score, and previous obstetrical history. When multivariate analysis was performed, only CL and previous obstetrical history correlated significantly with mode of delivery. In the subgroup of patients with no previous vaginal delivery, only CL had a significant correlation with mode of delivery. The ROC curve demonstrated a high prediction of vaginal delivery by CL for the entire study group and for the subgroup of patients with no previous vaginal delivery (AUC = 0.8, p < .0001).

Conclusions: CL measurement after 36 weeks has a high predictive accuracy for a successful vaginal birth after cesarean.

Keywords:

• Cervical length
• vaginal birth after cesarean
• TOLAC
• cesarean delivery

Disclosure statement

The authors report no conflict of interest.