There are different types of contraceptive pills, and the effects of the pills are different after use. Common contraceptives include short-acting oral contraceptives, emergency contraceptives, and long-acting contraceptives.1 Short-acting oral contraceptives have a contraceptive effect within 24 hours of taking them, but they need to be used continuously according to the menstrual cycle, for example, they need to be used on the fifth day of menstrual bleeding in order to ensure that the contraceptive effect is maintained and the menstrual cycle is not disturbed.2 Emergency contraceptives have a contraceptive effect only when taken no more than 72 hours after having sex.3 Emergency contraceptives have a contraceptive effect when taken no more than 72 hours after having sex. The pill is only effective in preventing pregnancy if it is taken more than 72 hours after sexual intercourse. After more than 72 hours after taking the drug is no contraceptive effect, and is not a regular means of contraception, can not be used more than 3 times a year. 3, long-acting contraceptive pills, the use of a piece of every month, in the use of the drug before the need to use a short-acting oral contraceptive transition, as long as the use of the drug, within 1 month are the existence of contraceptive effect.