1. Severe pregnancy-induced hypertension syndrome, which is ineffective after treatment, requires delivery as soon as possible, and does not meet the conditions for vaginal delivery. 2. The pregnancy is complicated by heart disease, but the conditions for vaginal delivery are not met. 3. Those who have a history of cesarean section or surgical scars, the operation time is less than two years, or there is a history of postoperative complications or wound dehiscence, and the fetus is larger at this time