There are blood spots in the underwear after every urination, and there are no problems in gynecology and urethra. You can consider ovulation bleeding, sexual bleeding, as well as kidney stones and nephritis. 1. Ovulation bleeding: physiological bleeding occurs during ovulation, there will be a small amount of blood after urination, which lasts for about 1~3 days and will disappear on its own without special treatment. 2. Bleeding after sex: After sex, the vaginal mucosa will be damaged, causing bleeding after urination, but the amount of bleeding is relatively small. 3. Kidney stones, nephritis: Kidney metabolism is abnormal, kidney stones will affect normal urination, resulting in difficulty in urination and bleeding after urination. There are many reasons why there are blood spots in the underwear after each urination, and if you can’t determine the cause, it is recommended that you go to a professional hospital for consultation and treatment.