What causes a small amount of bleeding after sleeping together?

A small amount of bleeding after the same room, mostly because the same room time is too long, damage to the vaginal mucosa caused. Or contact bleeding reasons, such as cervicitis, cervical cancer, etc. Cervicitis is due to bacterial infection of the uterine neck, caused by an inflammatory disease. Cervical cancer and the body long-term suffering from high-risk HPV virus infection.