In the clinic there is no separate role of 72 hours of contraceptive pills, contraceptive pills are mainly the following: 1, compound short-acting contraceptive pills: required to be taken from the fifth day of menstruation, after a week of continuous use before the contraceptive effect, and each cycle needs to be taken continuously 21-28 days, before the normal menstrual cycle, there is a better contraceptive effect. 2, compound long-acting contraceptive pills: after taking a piece can 3, family visit contraceptive pill: family visit contraceptive pill need to take a relatively short time, but also need to take several times, especially in the days of family visits need to take, but because of its side effects are very large, in the clinic has been rarely used. 4, emergency contraceptive pill: required within 72 hours of unprotected sex, or mifepristone can be taken within 120 hours.