After taking the emergency contraceptive pill Mifepristone, there was bleeding. Is it a failure to prevent pregnancy?

Patient's question:

No

Doctor's answer:

Emergency contraception pills can cause irregular menstruation in women. If taken during the first half of the menstrual cycle, they may have a greater impact on a woman's menstruation, making it more likely to experience vaginal bleeding. If taken during the second half of the menstrual cycle, the interference with a woman's menstruation is smaller. If the amount of bleeding is similar to her usual menstrual flow, it can be considered as one menstrual period. After the bleeding stops, conventional contraception methods should be immediately adopted. If the bleeding is very light, no treatment is necessary.