After taking emergency contraceptive pills, menstruation is usually delayed within 1 week, but the exact delay varies from person to person. The main component of the emergency contraceptive pill is the progestin levonorgestrel, which is mainly used for contraception by inhibiting ovulation, preventing sperm from combining with the egg, and preventing the fertilized egg from implanting in the uterus. Generally is the contraceptive measures failed remedy, within 72 hours after coitus to take, the earlier the contraceptive effect of taking the better. As emergency contraceptive pills contain a large number of hormones, it is easy to lead to menstrual disorders, and generally delay menstruation for no more than 1 week. Allergies should be used with caution. If the menstrual period is delayed for more than 1 week or does not come, it is recommended to go to the local hospital obstetrics and gynecology clinic in a timely manner to rule out the possibility of contraceptive failure, and be sure to comply with the doctor’s instructions to deal with the treatment.