After taking emergency contraceptive pills, menstruation only one day is needed to check the HCG to rule out pregnancy, but also may be emergency contraceptive pills caused by irregular vaginal bleeding or menstrual disorders, you can first observe. Clinically there is no 100% contraceptive method, so the oral emergency contraceptive pills may also have the phenomenon of pregnancy, if the current menstrual period has obvious abnormalities, then it is first recommended to check the blood HCG to see if the bleeding is caused by pregnancy, not menstrual flow. Some girls taking emergency contraceptive pills may cause irregular vaginal bleeding or menstrual disorders, you can first observe. If you have abnormal vaginal bleeding after taking emergency contraceptive pills, it is recommended that you consult a doctor to find out the cause of the bleeding, and actively treat the symptoms.