Uterine scar rupture - Prediction, prevention, diagnosis, and management

The increasing rate of elective and indicated caesarean sections worldwide has led to new pathologies and management challenges. The number of patients undergoing trial of labor after caesarean section (TOLAC) is also increasing. Three professional societies provide detailed guidelines based on scientific evidence for the management of patients attempting vaginal birth after caesarean section (VBAC). However, they do not provide any recommendations for the actual surgical steps to be followed to minimize the risks of uterine rupture (UR) during TOLAC. Uterine scar condition, intrapartum management and maternal health status correlate to uterine scar rupture risk and provide guidance for parturient TOLAC eligibility. TOLAC and vaginal delivery success rate as reported by the largest studies is between 60% and 77%. Uterine rupture is more prevalent in VBAC-2 patients (1.59%) in contrast to VBAC-1 (0.72%). Additionally, VBAC-2 patients have higher incidence of caesarean hysterectomy 0.56% vs. 0.19% for VBAC-1. The chances of successful VBAC increase when the interpregnancy/interdelivery interval is less than 6.3 years and less than 24 months, respectively. No difference was detected between the techniques of uterine incision closure of the previous CS and TOLAC results, although closure of the CS uterine incision in 2 layers seems to be practiced more widely. Niche or isthmocele presents another complication of CS. Secondary infertility due to niche, will eventually direct to hysteroscopic or laparoscopic repair, depending on the residual myometrial thickness (RMT) as measured by US scan. When RMT is below 3 mm or 2.5 mm surgery can be performed, to prevent any spontaneous UR in case of pregnancy. Monitoring by US scanning of hysterotomy scar after myomectomy can detect hematoma. In patients with severe postoperative pain but hemodynamically stable follow up by US scan examination can direct the management decision. In those patients with active bleeding and deterioration of hysterotomy scar edema will be an indication to surgery. There is no firm evidence regarding which type of thread, knotting or sequence of suturing is more favorable to reduce the risk of UR after VBAC or hysterotomy after myomectomy.