The onset of menstruation in women is influenced by the level of hormones in the body and can be caused by the presence of tumors in the body. The most common type of tumor is choriocarcinoma, which occurs after a gravida pregnancy. Women with choriocarcinoma may experience irregular vaginal bleeding in small amounts and may have a false pregnancy reaction during the examination because of an abnormal increase in HCG levels, breast enlargement, and softening of the reproductive tract. When suffering from endometrial cancer or ovarian cancer, there will also be no menstrual flow. When women do not have menstrual flow, it is recommended to rule out the possibility of pregnancy through early pregnancy test or blood sampling. Consider whether it is caused by gynecological diseases, and treat the symptoms through gynecological examination. Also consider whether it is caused by cancer, and hormone-secreting tumors may also cause women not to have periods.