There are three main types of emergency contraceptive pills in clinical practice: first, the highly effective progestin-based emergency contraceptive pills. Second, the combination of estrogen and progestin emergency contraceptive pills. The third, mifepristone-based emergency contraceptive pill, these three types of emergency contraceptive pills will not lead to fetal malformation. Progesterone-based or estrogen-progestin-based emergency contraceptive pills, after the failure of contraception, the patient can have a normal pregnancy, because these two drugs themselves do not have any bad effects on the embryo, but rather conducive to the preservation of the fetus. Because in the early stages of pregnancy, patients can use estrogen or progestin to preserve the fetus when miscarriage occurs. Mifepristone-based emergency contraceptive pills after taking, the patient after pregnancy is generally not recommended to continue the pregnancy. Because mifepristone is a progesterone antagonist, mainly through the competition for progesterone receptors to inactivate the action of progesterone, so as to achieve the effect of contraception or abortion, but it will not lead to malformation of the embryo.