The bloody discharge in the middle of menstruation is considered to be related to ovulation bleeding, polyps, uterine fibroids, and pregnancy-related diseases. 1. Ovulation bleeding: for women, due to the significant drop in estrogen levels during ovulation, some women will experience a small amount of endometrial stripping and a small amount of vaginal bleeding, usually lasts for 2~3 days can be stopped. 2. Polyps: For women with endometrial polyps or cervical polyps, irregular vaginal bleeding is the main clinical manifestation, and a small amount of vaginal bleeding may occur in the middle of menstruation. 3. Uterine fibroids: For patients with uterine fibroids, due to the increase in uterine volume and endometrial surface area, women may experience irregular vaginal bleeding or heavy menstrual flow. 4. Pregnancy-related diseases: for women of childbearing age who have normal sex life, the first thing to be excluded is the possibility of pregnancy-related diseases such as early pregnancy, preeclampsia, ectopic pregnancy, etc. For women with bloody discharge in the middle of menstruation, they may have irregular vaginal bleeding or heavy menstruation. For women with bloody discharge in the middle of menstruation, it is recommended that they go to the gynecology department of a regular hospital to improve ultrasound and other relevant examinations, and then be treated under the guidance of the doctor after clarifying the cause of the disease.