The regular short-acting contraceptive pill is taken on the fifth day of menstruation, the first pill is taken for 21 days, and the second cycle is started 7 days after stopping the pill. If you miss a dose, you should take it early and be alert to the possibility of pregnancy. If you miss 2 pills, you will need to add other contraceptive measures after taking the pill, as the chance of pregnancy is very high. However, if you miss three pills, you will need to wait for your period before starting a cycle. The compounded short-acting contraceptive pill mainly inhibits ovulation, and the contraceptive rate can be as high as 100 percent when the pill is taken regularly. It is important to be aware of any adverse reactions to the pill and to stop taking it if necessary.