A more accurate way to determine the success of contraception by taking emergency contraceptive pills is to check the blood for human chorionic gonadotropin more than 7-10 days after sexual intercourse, which also includes observing whether the next menstrual period is coming or not. Human chorionic gonadotropin, or HCG, can be detected in the peripheral blood after the fertilized egg has been deposited. It takes at least 7 days, and there may be a few days of error during this period due to individual differences, so most of the contraceptives can be judged to be successful when the blood test for HCG is negative after at least 7-10 days. In addition to checking blood HCG, other common methods of judgment include observing whether the next menstrual period is coming or not. However, this method of judgment is not accurate. If vaginal bleeding occurs on the date of the next menstrual period, it cannot be judged to be the onset of menstruation, but may be a sign of miscarriage, and some patients may mistake bleeding from a miscarriage for the onset of menstruation. Patients who want to determine whether emergency contraceptive pills are successful or not can check blood HCG more than 7-10 days after sexual intercourse. However, if any abnormal symptoms appear after taking the pills, it is recommended to consult a doctor in time so as not to delay the condition.