Introduction: There is significant public and professional concern over the rising rate of caesarean section deliveries.
Objective: To evaluate lower uterine segment thickness by transvaginal and abdominal ultrasound in women with a previous cesarean delivery and to determine a critical thickness above which safe vaginal delivery is predictable.
Methods: A case-control study included 50 pregnant women with a history of previous one cesarean delivery constitute the case group and 50 pregnant women without history of previous cesarean section constitute the controls. Gestational age was between 38-40 weeks of gestation. TA and TV ultrasonography were used in both groups to evaluate LUS thickness, in the study group, >2 mm of thickness of the LUS was considered as good healing and <2 mm of thickness as poor healing, women were categorized for the mode of delivery into either trial of VBAC (unless an obstetrical indication for CS existed) or ERCS. All the intraoperative LUS appearance and delivery outcome were correlated with U/S measurements.
Result: The overall VBAC was 84% and VBAC success rate was 52%, the incidence of dehiscence was 4%, and there was no uterine rupture. There was a 95% correlation between TA ultrasonography and TV ultrasonography. The critical cut off value for safe LUS thickness, derived from the ROC curve, was 2.5 mm.
Conclusion: Sonography permits accurate assessment of the LUS thickness in women with previous cesarean section and therefore can potentially is used to predict the risk of uterine rupture during trial of vaginal birth.