In the case of unprotected, had sex once, have taken the emergency contraceptive pill, how to determine the success of emergency contraception? 1.Self-judgment: Is the menstruation coming as expected? After taking the emergency contraceptive pill, if a woman has a normal period, it means that there is no unwanted pregnancy, that is, the emergency contraception is successful. The irregular vaginal bleeding that occurs in most people after about 1 week of taking the pill does not often mean that the contraception is successful. Irregular vaginal bleeding after taking the pill is mainly due to withdrawal bleeding caused by the drug and is not harmful to the body and can be left untreated, usually returning to normal menstruation after 1 to 2 menstrual cycles. Therefore, if irregular vaginal bleeding occurs along with other abnormal symptoms such as lower abdominal pain, you should seek medical attention promptly. In conclusion, women should pay close attention to the change of menstruation after taking emergency contraceptive pills, especially when the expected delay of menstruation is more than 1 week, they should go to hospital for examination in time to clarify whether they are pregnant and pay attention to exclude ectopic pregnancy. 2.Visit medical test: 7~10 days after taking the pill, go to the hospital to check blood HCG or urine HCG If you are really unsure, women can go to the hospital to check blood HCG or urine HCG 7~10 days after taking the emergency contraceptive pill, which is a safer way to determine whether you are pregnant or not. If the blood HCG or urine HCG result shows negative, it means no pregnancy, that is, the emergency contraception is successful. Warm tips: 1, the emergency contraceptive pill can not be used as a regular contraceptive method, only after the fact contraception. 2. The emergency contraceptive pill should be used within 72 hours of intercourse, and the earlier it is used, the better the effect. References: [1] Cheng Linan, Safety of emergency contraceptive pills. Journal of Practical Obstetrics and Gynecology [R],2014,30(7):488-490.