VBAC Risk Score for Successful Vaginal Delivery (Flamm Model)Loading...Maternal age < 40 yearsNo0Yes+2Vaginal birth historyNo previous vaginal birth0Vaginal birth before cesarean delivery+1Vaginal birth after cesarean delivery+2Vaginal birth before and after first cesarean delivery+4Reason other than failure to progress for first cesarean deliveryNo0Yes+1Cervical effacement at admission< 25%025-75%+1> 75%+2Cervical dilation ≥ 4 cm at admissionNo0Yes+1