Sep 6, - Vaginal bleeding after sex (also known as postcoital bleeding) is not an entirely uncommon situation among menstruating women, and it's even. Jump to What happens at the doctor's appointment? - Most aren't cancerous, and a doctor can remove them during an appointment. Other causes of vaginal bleeding after sex include: Friction during sex or not enough lubrication. Cervical ectropion (when the inner lining of the cervix pokes through the cervical opening and grows on the vaginal side of the cervix).