Oral emergency contraceptive pills may cause amenorrhea. As emergency contraceptive pills inhibit ovulation and alter the ovarian estrogen and progesterone secretion cycle, they break the natural menstrual pattern, leading to menstrual disorders and even amenorrhea in some women. It may also have irreversible effects on the ovaries. In this case, it is recommended to first rule out the possibility of pregnancy. Although oral emergency contraceptive pills have a contraceptive effect, they are more harmful to women, not only causing menstrual disorders, but also may cause amenorrhea, and even irregular vaginal bleeding and so on. You can choose effective contraceptive methods, such as condoms, during intercourse. If there is still no menstruation on the 8th day of non-pregnancy, it is recommended to go to the hospital for examination to rule out the possibility of premature ovarian failure or pelvic tumor.