Regular vacation generally stands in for menstruation. Bleeding after half a month of menstruation may be caused by ovulation, cervical inflammation, endometrial polyps, perimenopause, cervical cancer and endometrial cancer. 1. Ovulation: Hormonal changes in the body during ovulation can also cause a small amount of vaginal bleeding, a small amount, accompanied by a slight pain in the lower abdomen, which can occur about half a month after menstruation and is a physiological phenomenon. 2. Cervical inflammation: due to inflammatory stimulation of the cervical canal mucous membrane is brittle, easy to bleed, can occur premenstrual bleeding, bleeding after coitus and other symptoms, can also be accompanied by an increase in vaginal discharge, can be combined with the history of gynecological examination, vaginal secretion examination to assist in the diagnosis. 3. Endometrial polyps: Polyps can affect uterine contraction leading to bleeding between periods, heavy menstrual flow, prolonged menstrual period and other symptoms, which can be diagnosed by ultrasonography, hysteroscopy and so on. 4. Perimenopause: due to the decline of ovarian function and hormone level in the body, menstrual disorders are caused, manifested as irregular menstrual cycle, increased or decreased menstrual flow, etc. The diagnosis can be assisted by history and hormone measurement. 5. Cervical cancer: mainly manifested as contact bleeding from the cervix, such as after coitus or gynecological examination, accompanied by rice-water-like vaginal discharge with fishy smell, which can be diagnosed by combining with medical history, cervical cytology and cervical biopsy. 6. Endometrial cancer: it may also manifest as bleeding between menstrual periods, prolonged menstrual period, increased menstrual flow, etc. It may also be accompanied by plasma discharge, which can be combined with medical history and ultrasonography, hysteroscopy, etc. to assist in diagnosis. Therefore, it is necessary to go to the hospital when bleeding occurs again after half a month of menstruation in order to find out the cause and handle it under the guidance of the doctor.