Women who take the emergency contraceptive pill before ovulation may experience vaginal bleeding 3-7 days after stopping the pill, which is equivalent to having a menstrual period. In contrast, when taking the emergency contraceptive pill after ovulation, the time of menstruation is no different than usual. Vaginal bleeding after taking the emergency contraceptive pill before ovulation is due to the withdrawal of progesterone, causing the endometrium to shed and resulting in bleeding, which is a kind of withdrawal bleeding. The duration and amount of bleeding are no different from normal menstrual bleeding. The time of the next menstrual period is calculated from this bleeding, and usually a woman will have her menstrual period 21-35 days after this bleeding. However, if a woman takes the emergency contraceptive pill after ovulation, because her body has already secreted progesterone, it may not cause withdrawal bleeding after taking the pill, and the time of menstruation will come according to the original menstrual cycle at this time. It is recommended that women adjust their mindset after taking the emergency contraceptive pill, relax, pay attention to rest and try to avoid large emotional fluctuations. If the period is delayed for a long time, it is necessary to consider whether the contraception has failed.