Suddenly having two periods in a month may be normal or abnormal. 1. Normal phenomenon: If the bleeding occurs in the period between two periods and the amount of bleeding is smaller than the normal amount of menstruation, it is considered that the hormone level of the body at the time of ovulation has a transient decline resulting in ovulation bleeding. In addition, adolescent women may have menstrual disorders due to the immaturity of the hypothalamus-pituitary-ovarian axis. Menopausal women will also experience abnormal menstruation due to fluctuating changes in hormone levels, all of which are normal. 2. Abnormal: Suddenly having menstruation twice a month may also be due to some diseases, such as uterine fibroids, endometrial polyps, endometrial cancer, etc., which can lead to localized bleeding in the uterus and cause abnormal bleeding. Also cervicitis, squamous intraepithelial lesions of the cervix, and cervical cancer can cause contact bleeding or irregular bleeding that can be mistaken for menstruation. All of these conditions are abnormal. Whether it is normal to have menstruation twice a month all of a sudden cannot be diagnosed directly, and it is recommended to go to the hospital in time for treatment of the cause.