There are many causes of bleeding during sexual intercourse, mostly related to female cervical lesions. Therefore, it is important to actively identify the cause and take symptomatic treatment. If it is the first time to have sex, the cause of bleeding is mostly hymen rupture. The bleeding is mostly not serious. If the bleeding is serious, it is recommended to seek medical attention promptly. Next, the following causes can be considered. A, cervical lesions 1, cervical erosion: cervical erosion is the most common inflammatory disease of the female reproductive organs, especially married women, about half of them have different degrees of cervical erosion. 2.Cervical polyps: polyps are brittle and bleed when touched, so there can be bleeding after intercourse, mostly bright red. 3. Cervical cancer II. Endometriosis If endometriosis occurs in the cervix, it will easily rupture and bleed after contact. III. Intrauterine device Most often occurs in women with early intrauterine device. As the mechanical compression of the IUD can lead to local damage of the endometrium, it will mostly cause bleeding after intercourse. Fourth, vaginal infection For example: Chlamydia infection, trichomonas vaginalis, etc. Therefore, whatever the cause of post-coital bleeding, it is important to pay attention to it. At the same time, to do a good job of prevention. Prolonged bleeding during sexual intercourse can easily increase the risk of infection and also aggravate the progression of cervicitis. Therefore, when sexual bleeding occurs, it is important to actively seek medical attention to identify the cause and give symptomatic treatment.