The common contraceptive pills are divided into short-acting pills and emergency pills. For example, the short-acting contraceptive pill is to be taken orally on the 1st-5th days of menstruation, one pill per day, and after taking a box of the pill, menstruation will come in 5-7 days, then this time is normal. However, if it takes more than 10 days and there is no menstruation, then there is an abnormality. For example, after taking emergency contraceptive drugs, the hormonal secretion of the endometrium can be altered by the oral administration of emergency contraceptive drugs, which may affect the menstruation. For example, it may cause early menstruation, which is normal if it is 3-5 days early and not more than 7 days early. It may also cause a delay in menstruation, usually for 7-10 days, which is normal as long as it does not exceed 10 days. However, oral contraceptives do not have a 100% chance of success, so when your period is delayed for a long time after taking them, try to rule out the possibility of pregnancy.