If you have intercourse without contraception, you need to take the emergency contraceptive pill orally within 72 hours after intercourse. Some birth control pills require two pills to achieve the contraceptive effect, while some emergency contraceptive pills can achieve the contraceptive effect by taking just one pill. Therefore, it is important to read the instructions in detail before taking the oral emergency contraceptive pill, so that it will not lead to the wrong method of taking the pill. In addition, the emergency contraceptive pill will clinically inhibit ovulation and cause abnormal thickening of the endometrium, preventing the fertilized egg from being laid in order to achieve the purpose of contraception. When the pill is discontinued, withdrawal bleeding will occur, usually in small amounts and less than menstruation, and will clear up on its own in 3-5 days. In addition, it is recommended not to take emergency contraceptive pills as a regular contraceptive method in daily life, but to use condoms if you are not planning to get pregnant.