The ultrasound examination to CS time interval varied from one to forty eight hours. During Cesarean delivery the LUS was defined as the part of the uterus below the uterovesical peritoneal reflection. After opening the visceral peritoneum and performing the bladder dissection, the LUS was assessed for integrity of the CS scar by the operating surgeon to avoid bias by the sonographic findings. Scar dehiscence was defined as the presence of either transparent LUS with visible contents, presence of well-circumscribed scar defect or presence of frank uterine rupture.