Menstruation is not necessarily delayed after taking the emergency contraceptive pill, some of them may be delayed for about 1 week, which is mostly normal and should be judged in the context of your own situation. The emergency contraceptive pill contains a lot of estrogen and progestin, and most of them will have withdrawal bleeding 3-7 days after taking the pill, but this is due to the bleeding caused by the pill, not menstruation. Whether there is withdrawal bleeding or delayed menstruation is mainly related to the time of taking the emergency contraceptive pill. The effect of taking emergency contraceptive drugs on the body varies greatly from one period to another: follicular phase, ovulation phase, and luteal phase. If you take emergency contraceptive pills during ovulation, the withdrawal bleeding and menstruation may coincide after stopping the pills, which can be regarded as a normal menstrual flow. Emergency contraceptive drugs are best taken on an empty stomach to avoid diet affecting the absorption of the drug and leading to contraceptive failure. If your period is delayed for more than half a month, you need to check the urine pregnancy test or blood HCG test in time to rule out the possibility of pregnancy.