When there is blood in the lower part of the uterus but it is not menstruation, abnormal bleeding from the uterus should be considered, and attention should be paid to bleeding caused by ulcerative bleeding, bleeding caused by changes in hormone levels, and bleeding caused by systemic diseases. 1. Bleeding due to breakage (1) Bleeding caused by trauma, vulvar or vaginal injury, hymen and vaginal injury caused by sexual intercourse can cause bleeding. (2) Bleeding caused by soft birth canal laceration after delivery, gynecological related surgeries such as curettage. (3) Bleeding caused by gynecological inflammatory diseases. (4) Bleeding caused by cervical polyps. (5) Certain gynecological tumors combined with infection and necrosis may cause abnormal bleeding. 2. Bleeding caused by hormone level changes (1) External use of some hormones, such as estrogen, progesterone, etc., may cause endometrial shedding and bleeding. (2) After placing intrauterine device, the activity of fibrinolytic system is enhanced, which may easily lead to irregular vaginal bleeding. 3. Bleeding caused by systemic diseases (1) Abnormal bleeding caused by leukemia, aplastic anemia, thrombocytopenic purpura and other hematologic diseases. (2) Abnormal uterine bleeding caused by decreased synthesis of clotting factors by the liver in the case of severe hepatic insufficiency. When bleeding that is not menstruation occurs, it is important to actively seek medical attention in the hospital to find out the cause.