There are many types of birth control pills, and in the case of short-acting birth control pills, most will result in a period within 7 days of stopping the pill. If you need to continue taking oral contraceptives, you can start the next course of medication 7 days after stopping the pill. If oral emergency contraceptive pills are taken, the next menstrual period normally follows the last menstrual cycle. If the oral emergency contraceptive pill for the middle of menstruation, many women will be in the oral 3-5 days after the withdrawal bleeding, because at this time the thickness of the endothelium reached the menstrual period led to the clinical can not be based on the presence or absence of withdrawal bleeding to determine whether the contraception is successful. If there is a delay in menstruation for 7 days, you need to rule out pregnancy first. If there is irregular vaginal bleeding, it may be due to menstrual disorders caused by contraceptive pills, or it may be due to abnormal pregnancy, and you need to consult a doctor for examination to find out whether it is menstrual disorders, or miscarriage with precursor signs, or ectopic pregnancy.