Small amount of vaginal bleeding before menstruation is common for the following clinical reasons: 1. Inflammation of the endometrium, which is accompanied by pain in the lower abdomen and odorous discharge. 2. Endometriosis, which is often accompanied by severe dysmenorrhea. 3. Small amount of premenstrual bleeding due to endocrine disorders, such as 4. Small amount of bleeding before menstruation due to inflammation of the endometrium. 5. Submucosal fibroids and endometrial polyps may cause bleeding before menstruation. For this condition, it is clinically recommended to do ultrasound examination first to understand whether there is any abnormality in the uterus and pelvis, and it is also recommended to draw blood to check sex hormone six.