Emergency contraception is an active intervention that can prevent a large number of unplanned pregnancies due to unprotected sex or contraceptive failure and reduce the resulting maternal mortality and the incidence of associated gynecological diseases due to unsafe abortion. In China, numerous feasible contraceptive technologies are available, but contraceptive coverage among Chinese adolescents is very low. Therefore, emergency contraception is urgently needed even if there is no planned pregnancy, frequent exposure to unprotected sex or contraceptive failure (condom breakage, missed doses of the pill, etc.) or even the occurrence of sexual assault. The judicious use of emergency contraception is advocated for unprotected sex and unwanted pregnancies to reduce the rate of repeat abortions. As the name suggests, it is used only for emergency contraceptive status and not for routine or repeated use. The emergency contraceptive pill is only effective for the first few days after intercourse, i.e. before ovulation or sperm-egg union. The emergency contraceptive pill does not prevent an existing pregnancy or damage a developing embryo or cause an abortion. It is effective in stopping 85% of unintended pregnancies but cannot be used routinely.