The phenomenon of small amount of bleeding without menstruation, consider the following possible causes: 1. Ovulation bleeding, this is more likely, due to insufficient support of hormone levels in the body, it happens occasionally and lasts about 3 days, the amount of blood is particularly small without special treatment, most of them can stop by themselves. 2. You should do gynecological ultrasound examination to observe whether there are abnormalities in the uterus, adnexa and endometrium, if the uterus If the endometrium has excessive hyperplasia or endometrial polyps, there will be a small amount of bleeding. 3. do a routine white belt examination to determine whether there is vaginal inflammation, more serious vaginitis can also appear a small amount of bleeding. 4. do a gynecological internal examination to diagnose whether there is chronic cervicitis or cervical polyps. It is recommended to do the above examinations according to personal situation and to check each item.