There are many reasons why a woman may bleed after sex. The medical name for this is “postcoital bleeding”. Postcoital bleeding refers to genital bleeding after intercourse. Doctors generally use this term to describe vaginal bleeding, a fairly common occurrence caused by a wide range of factors. Approximately 9% of menstruating women experience postcoital bleeding, mostly from the cervix. The source of this bleeding is usually more varied in postmenopausal women. Common causes of bleeding after sex include: Injury Friction during intercourse can easily cause small tears and cuts in the sensitive genital tissues. Childbirth can also cause vaginal tissues to stretch and tear, sometimes making them more vulnerable to injury. Vaginal dryness Dryness is among the most common causes of postcoital bleeding. When skin is dry, it becomes extremely vulnerable to damage. Mucus-producing tissues, such as those in the vagina, are particularly vulnerable. The common causes of vaginal dryness can be several. Genitourinary syndrome of menopause. Once called vaginal atrophy, it refers to decreased thickness and elasticity of vaginal tissue. Damage or removal of the ovaries. Severe accidents that damage the ovaries or conditions that lead to their removal destroy the body’s largest source of estrogen. Childbirth and breastfeeding. During pregnancy, estrogen levels are very high. However, they decrease almost immediately after birth, as estrogen can interfere with the production of breast milk. Medicines that interfere with estrogen or dehydrate the body. Vaginal dryness can result from taking anti-estrogen medications, cold or flu medications, steroids, sedatives, certain types of antidepressants, beta blockers, or calcium channel blockers. Infections Any type of infection can cause inflammation of the vaginal tissues, making them more vulnerable to damage. These commonly include yeast infections, pelvic inflammatory disease, cervicitis, vaginitis, and sexually transmitted infections such as chlamydia and gonorrhea. Cervical or endometrial polyps or fibroids Polyps and fibroids are small non-cancerous growths. They usually grow on the lining of the cervix or uterus, especially during menstruation they can cause pain and bleeding. Cervical ectropion Glandular cells on the inside of the cervical canal can grow abnormally on the outside of the cervix. This condition usually goes away without treatment, but it can cause spotting and vaginal bleeding. Endometriosis Endometriosis causes the endometrial tissues, those lining the uterus, to grow outside of it. This can cause inflammation, usually in the pelvic area and lower abdomen. Cervical Dysplasia Cervical dysplasia occurs when abnormal,precancerous cells grow in the lining of the cervical canal. These growths can irritate and possibly damage the surrounding tissue, especially during intercourse. Anatomical abnormalities Some women have differently shaped reproductive organs, which can increase the likelihood of painful rubbing and tearing. Blood coagulation disorders Diseases that cause abnormal bleeding or clotting may increase the risk of postcoital bleeding. Blood thinning medications can also have this effect. Malignancies Cancers that affect the reproductive system or urogenital tract can alter vaginal tissues and hormone levels, making them more vulnerable to damage. Postcoital bleeding is considered a common symptom of both cervical and uterine cancer. References: Intermenstrual and postcoital bleeding Obstetrics, Gynecology and Reproductive Medicine 2015