Bleeding after sex can happen for several reasons, mostly related to the cervix, vaginal tissue, or hormonal and infection-related causes. Common causes include:

• Cervicitis: Inflammation or infection of the cervix, often due to sexually transmitted infections (STIs) like chlamydia or gonorrhea, or non-sexually transmitted infections such as yeast infections, causing fragile cervical tissues that bleed after sex.
• Cervical polyps: Small benign growths on the cervix that may bleed when irritated.
• Vaginal dryness or friction: Lack of lubrication during sex can cause irritation, friction, or small tears in vaginal tissues leading to bleeding.
• Cervical ectropion: A condition where cells from the inner cervix protrude to the outer cervix, making the area more prone to bleeding.
• Other causes: Genital sores, uterine prolapse, hormonal birth control effects, improperly placed intrauterine devices (IUDs), trauma, and, rarely, cervical, vaginal, or uterine cancer.

Bleeding after sex can be light or more pronounced, and while often not serious, persistent or heavy bleeding should be evaluated by a healthcare provider to rule out infections, precancerous conditions, or other serious issues.