Almost all obstetricians have a question: Is it safe to try to deliver vaginally in patients with scarred uterus? Almost all mothers-to-be who had their first cesarean delivery are also worried about one question: can scarred uterus deliver their second child vaginally? At present, the gradual opening of the second child policy in China and the lack of relevant guideline literature have added to the doubts in most people’s mind. In fact, both elective repeat cesarean delivery and attempted vaginal birth in scarred uterus (VBAV) are at risk. Failed vaginal attempts may be associated with serious complications for the mother, with increased chances of uterine rupture, hysterectomy, surgical injury, maternal infection and blood transfusion. Uterine rupture, if it occurs, would be a huge threat to the life of the mother and child. In addition, the rate of neonatal complications increases accordingly. However, there are also risks to the mother from multiple cesarean deliveries, including an increased incidence of placenta praevia and placental implantation. According to the ACOG guidelines for vaginal delivery after cesarean section, the indications for vaginal delivery in patients with scarred uterus are as follows: 1. Previous cesarean section with transverse incision of the lower uterine segment. No intraoperative incisional tear, good postoperative incisional healing and no infection. 2. The pregnancy is 2 years or more from the previous cesarean delivery. 3.Ultrasound indicates that the thickness of the anterior wall scar of the lower uterine segment is 2-4 mm or more, with no weak area. 4.No history of uterine scarring or uterine rupture such as myomectomy, hysteroscopic electrodesis. 5.Ultrasound examination was performed to assess the fetal size before the vaginal trial of labor, and the fetal weight was less than 4000g. 6.The previous indication for cesarean delivery no longer existed and no new indication for cesarean delivery appeared. 7.No serious pregnancy complications, no other medical or surgical complications that are not suitable for vaginal delivery. 8. The labor progressed smoothly during the trial of labor; the pregnancy was eligible for vaginal delivery, and there were no abnormalities in the three elements of labor; the pelvic measurement was normal. 9, fetal death in utero or fetus with serious malformation. 10, there is better medical monitoring equipment, physicians can be present at any time to monitor the delivery, can immediately anesthesia, emergency cesarean section staff can be present at any time, with the conditions of surgery, blood transfusion and resuscitation.