Emergency contraceptive pills should generally be used within 72 hours of sexual intercourse, and the earlier they are taken, the more effective the contraceptive effect. Emergency contraceptive pills are synthetic estrogen-progestin preparations, which play the role of emergency contraception by stopping or delaying the discharge of follicles in the ovaries, and is a contraceptive method for women who have sex without taking any protective measures, and should be used within 72 hours after sex, and the earlier you take it, the better the contraceptive effect is, and if necessary, you need to add one more time after 12 hours of taking the pills. However, it should be noted that after taking emergency contraceptive pills, it is easy to cause irregular vaginal bleeding, menstrual disorders, abdominal pain and other discomforts, so for women who do not have the need for pregnancy, it is recommended to take condoms, birth control devices and other contraceptive measures to contraceptives, so as not to cause endocrine disorders in women or to affect the reproductive function of the woman.