There are many reasons for bleeding after intercourse, which may be caused by strenuous movements, contact bleeding from the cervix, or inflammation of the vagina. 1. Strenuous action: If the action during sex is too strenuous, it may cause the vaginal mucosa to break and cause bleeding. 2. Contact bleeding from the cervix: this is mostly seen in cervical polyps, severe inflammation of the cervix, cervical cancer, cervical pre-cancerous lesions, etc., which will rupture and bleed under the action of external force during sexual contact. 3. Inflammation of the vagina: If there is inflammation of the vagina, there may be localized mucous membrane rupture, which will lead to bleeding. Bleeding after intercourse may also have other reasons, it is recommended to go to the hospital in time to improve the relevant examination, under the guidance of professional doctors to clarify the cause of the disease, and active treatment, to avoid causing serious consequences.