When withdrawal bleeding occurs when taking birth control pills, it is generally good for contraception and indicates a relatively high probability of achieving contraceptive success. Withdrawal bleeding usually refers to vaginal bleeding symptoms that occur when a woman takes emergency contraceptive pills or uses medication to help shed the endometrium due to endocrine dysfunction, which often indicates that the medication has had a certain effect on the body, which makes it more likely that the contraceptive will be successful or that the endometrium will be successfully shed. Therefore, the withdrawal of bleeding is generally prove that the endometrium will be a drug response to a performance, it is worth noting that the need to take drugs that may lead to withdrawal bleeding should be standardized under the guidance of a doctor, do not blindly self-medication, in order to avoid adverse effects.