Post-coital bleeding is vaginal bleeding that occurs immediately following sexual intercourse. Even the slightest amount of post-coital bleeding should be taken seriously, as it might be the first and only symptom of the initial stages of cervical cancer. In most cases, this bleeding is from either the vagina or cervix; it is rarely from the uterus or elsewhere. Due to the possibility of a serious underlying condition, vaginal bleeding after sexual intercourse should be thoroughly evaluated by your physician.

Vaginal bleeding after sexual intercourse is quite common. Approximately one out of every twenty women report post-coital bleeding. The most common causes of post-coital vaginal bleeding are listed in the table below. There are a few additional rare causes that may also present with vaginal bleeding.

Table: Common causes of bleeding after sexual intercourse

CIN: Cervical Intraepithelial Neoplasia (precancerous lesions of cervical cancer)

The most concerning causes of post-coital bleeding are cervical cancer and cervical intraepithelial neoplasia (precancerous lesion of cervical cancer). However, cervical cancer and CIN are not the most common causes of post-coital bleeding; they are identified in approximately every two hundred cases of post-coital bleeding. Any suspicious case is thoroughly evaluated for cancer or precancerous lesions, as there might not be any additional symptoms in the initial stages of the disease. The CINs and early stages of cervical cancer are treatable.

Cervical polyps refer to outgrowths on the cervix. These lesions are sometimes cancerous and are therefore almost always excised. Endometrial polyps are outgrowths from the uterine wall. These cause post-coital bleeding only when they protrude through the cervix.

Cervical ectropion, also known as cervical erosion, can also cause post-coital bleeding. In this condition, the cells that normally line the vaginal portion of the cervix is replaced by a different type of cell. This type of cell lining is less resilient, resulting in bleeding even after the slightest injury.

Cervicitis is a general term that refers to inflammation of the cervix, which may result from a wide variety of causes. Cervicitis is most commonly caused by sexually transmitted infections, and some of the less common causes include allergy, chemical irritation, foreign devices like a diaphragm, etc. The sexually transmitted diseases that may cause post-coital bleeding include Chlamydia, Gonorrhea, and Genital warts. Post-coital bleeding may be accompanied by symptoms like bleeding between menses, vaginal discharge, and pain during sexual intercourse.

Vaginitis refers to inflammation of the vagina. Vaginitis is most commonly caused by infections. Post-coital bleeding may occur with vaginitis, along with other symptoms such as vaginal discharge, foul odor, itching, swelling and redness of the vulva, pain during sexual intercourse, burning sensation during urination, etc. Atrophic vaginitis is a related condition caused by decreased levels of estrogen after menopause. This generally occurs due to decreased lubrication of the vagina.

Post-coital bleeding may also result from an injury sustained during rough sex. Another injury or trauma could also cause bleeding after intercourse. This could occur if her partner has any penile jewelry that may injure the vaginal walls.

In about two thirds of the patients with post-coital bleeding, no cause is identified. These cases are referred to as idiopathic. Almost any cause of vaginal bleeding can appear as post-coital bleeding if initially noticed after sex. It might be a mere coincidence that vaginal bleeding is first noticed after sexual intercourse. However, if a woman is sure that the bleeding only occurs after sexual intercourse, it is likely due to one of the common causes listed above.