The lack of withdrawal bleeding after taking emergency contraceptive pills is not necessarily a contraceptive failure. Emergency contraceptive pills are hormonal drugs. If you have sex in the first half of your menstrual cycle and take emergency contraceptive pills, you will usually experience withdrawal bleeding about 2-3 days after taking the pills. However, if the pill is taken in the second half of the menstrual cycle, because a woman will secrete progesterone after ovulation, the hormones in the drug will be superimposed on her own progesterone, prompting the growth of the uterine lining, and retreating bleeding will no longer occur, but will occur during the normal menstrual period, which will show the onset of menstruation due to the shedding of the uterine lining. If menstruation is delayed for more than seven days, a blood HCG test can be done to clarify whether or not you are pregnant, and should not be judged by whether or not there is bleeding. Emergency contraceptive pills can affect a woman’s endocrine system, so try to use other contraceptive measures in your daily life.