Taking emergency contraceptive pills menstrual disorders is considered to be an adverse reaction caused by taking emergency contraceptive pills, but also to pay attention to the possibility of contraceptive failure after pregnancy abnormal vaginal bleeding. 1. drug side effects: the main component of emergency contraceptive pills is a large dose of progesterone, for the body’s hormone levels will have a great impact on the endocrine disorders, which can lead to menstrual disorders, mainly manifested in cycle changes or drenching and so on. 2. Contraceptive failure: Emergency contraceptive pills have the possibility of contraceptive failure, the vaginal bleeding at this time may not be menstruation, but abnormal bleeding after pregnancy, which may indicate the risk of preeclampsia. In conclusion, it is recommended to go to the hospital for blood test for sex hormone six and blood HCG to clarify the cause of the disease and then carry out targeted treatment.