Meanwhile, mortality rate of C/S is five times more than normal vaginal delivery,yet suffering severe pain affects women's decision on method of next deliveries. Although women's information about delivery process is usually obtained from friends and relatives, their unpleasant experiences of delivery could be transmitted to other women and fear of labor pain spreads out among women through an abnormal cycle and interest in C/S will be increased. Therefore, application of a safe and effective method for relieving labor pain is an essential topic in obstetrical studies.