No withdrawal bleeding after taking the pill may be a normal phenomenon, may also indicate contraceptive failure, according to the type of contraceptive pills and the time to take the pill comprehensive judgment. 1, emergency contraceptive pills: If patients take emergency contraceptive pills in the second half of the menstrual cycle, may not appear withdrawal bleeding, which is a normal phenomenon, on time to menstruation is proof of successful contraception. However, if the menstruation is delayed for more than 1 week, there is a possibility of contraceptive failure. In addition, if the patient has a lot of vaginal bleeding with abdominal pain, bleeding can not stop by itself and other symptoms, suggest that there may be ectopic pregnancy, need to promptly seek medical advice, abdominal ultrasound examination; 2, short-acting contraceptives: usually after the short-acting contraceptives stop, most women will have a sudden drop in hormone levels resulting in withdrawal vaginal bleeding, generally speaking, will not affect menstruation. If there is no withdrawal bleeding and menstruation is delayed for more than 1 week, it is suggested that the patient should go to the hospital for blood test to determine whether she is pregnant according to the concentration of blood chorionic gonadotropin; 3. Long-acting contraceptive pill: the principle is the same as emergency contraceptive pill. Generally no need to deal with, but need to clarify whether there is pregnancy.