Bleeding during intercourse three days after menstruation may be caused by inflammatory gynecological diseases, such as vaginitis, cervicitis, inflammatory secretions long-term stimulation of the mucous membrane, resulting in mucosal congestion, edema, mucosal blood vessel rupture, bleeding phenomenon will occur during intercourse. Bleeding may also be caused by cervical diseases, such as cervical polyps, cervical precancerous lesions, cervical cancer, contact bleeding can occur, and need to do cervical cancer screening to further exclude. In addition, some gynecological diseases, such as endometrial polyps, uterine submucous fibroids, uterine adenomyosis, etc., will have irregular vaginal bleeding, which has no relationship with whether or not to have coitus, but will stimulate the uterus to contract after coitus, causing bleeding. So if there is bleeding after coitus, you should consult the hospital in time for gynecological examination and relevant auxiliary examination to find out the cause. There may also be some physiological phenomena, such as ovulation bleeding, which can only be determined after ruling out abnormalities.