Contraception after sexual intercourse, also known as emergency contraception, refers to the method adopted by women to prevent pregnancy after unprotected sexual intercourse, which is a remedial measure. At present, there are the following contraceptive measures that can be used after sexual intercourse: 1. High dose estrogen: oral diethylstilbestrol 25 ~ 50 mg per day for 4 ~ 6 days. This method has great side effects such as nausea and vomiting, and is no longer the first choice. 2. Oral contraceptive tablets (containing levonorgestrel 0.25mg and ethinylestradiol 50g); Take 2 tablets within 72 hours after sexual intercourse and 2 tablets after 12 hours. 3. Progesterone alone: take levonorgestrel 0.75 mg within 48 hours after sexual intercourse, 12 hours later. 4. IUD: place the copper-containing IUD within 5 days after unprotected sex. This method is most suitable for women who are contraindicated in hormone use. 5. Mifepristone: Take 600 mg Mifepristone within 72 hours after unprotected sex. Some can use 500 mg. You can choose the above methods according to your own situation, but these methods are temporary and should not be used frequently.