Whether the “wet spot” on the bed after sex turns out to be blood, or there is spotting on toilet paper when you wipe, bleeding after sex is a disconcerting climax to intimacy. There are two basic culprits that can cause bleeding after sex (also known as postcoital bleeding or PCB). The first potential problems are with the cervix. The second tier of possibilities encompass things that cause bleeding from the lining of the uterus.
Bleeding from the Cervix
Bleeding coming from the cervix could come from a cervical lesion – if one has had a recent normal PAP smear this is thought to be unlikely. One study found that only 49% of British gynecologists will do a repeat PAP if the woman with bleeding after sex has had a recent, normal PAP smear (Alfhaily, 2009). However, several studies from colposcopy clinics have found, even with a normal PAP, women with postcoital bleeding did have abnormal cells of the cervix. The rates for abnormal cervical cells ranged from 2.2% of high grade SIL (Ray & Kaul, 2008) to 9% of CIN (Khattab, 2005). The rate of actual cervical cancer was reported by Khattab to be 3.6%!
An infection of the cervix (cervicitis) can make the cervix more friable (easier to bleed). Both Gonorrhea and Chlamydia can produce bleeding from the cervix. Some 80% of British gynecologists report doing a Chlamydia screening on their patients with PCB. Thus, Chlamydia may be picked up by a primary care MD or GYN. By the time a woman is referred for colposcopy, only 2.3% of bleeding episodes after sex were linked to Chlamydia (Sahu, 2007).
In some women there is a normal enlargement of the area of glandular type tissue (cervical ectopi). These women can have bleeding even when the cervix is sampled with a PAP smear. Some common causes of cervical ectopi can include: being a young teenager, using birth control pills, or being pregnant. Studies have found that cervical ectopi can be the cause for bleeding after sex in 25% to 33.6% of cases.
A polyp coming from the cervical canal may bleed only when the cervix is touched. This could include sex toys, fingers, or a penis. Cervical polyps may account for 5% to 12.5% of bleeding after sex. Fortunately, most cervical polyps of this type can be readily seen during a speculum exam.
Bleeding from the Lining of the Uterus
If the uterine lining (endometrium) is easily destabilized, having sex can prompt spotting or breakthough bleeding. Some women will have this type of spotting if sex occurs during ovulation or right before menstrual flow is ready to begin. Women using hormonal forms of birth control may also have less stability of the uterine lining. Many birth control pill users have noted breakthrough bleeding after sex or even heavy exercise.
The same infections (eg Gonorrhea, Chlamydia) that infect the cervix can also infect the lining of the uterus. Infections of the uterine lining can make it easier to destabilize causing erratic bleeding as well as bleeding after sex.
Endometrial polyps or uterine fibroids can create a focus for unstable uterine lining. Additionally, some women with adenomyosis (endometriosis in the wall of the uterus) report bleeding after sex.
As WebMD readers know, if a woman has a history of missed periods, her uterine lining may be very thickened. In that situation, spotting after sex can represent small amounts of the lining being shed – just off the top layer.
Last, but certainly not least, pregnancy needs to be ruled out. Other, less common causes for bleeding include small tears in vaginal tissue. This would be most often seen in a postmenopausal woman who is not using estrogen-especially if she is resuming sex. If the spotting is after the first time having intercourse (losing your virginity) there can be spotting from tissues at the vaginal opening.
Could this bleeding after sex be no big deal?
Having heard about all the possible causes of bleeding after sex one would think that a culprit could be found to explain the bleeding. I was surprised to learn that, in three separate studies, about 50% of women evaluated showed no obvious reason for the bleeding! In each of these three studies women received thorough evaluations including colposcopies. However, given the multiple causes of bleeding after sex, one should go see a GYN if the spotting persists or is recurrent. When all the possible causes have been ruled out, then you might be one of the 50% where there is no pathological reason for the bleeding. Until a work up has been done, I would suggest that bleeding after sex is not a symptom to be ignored.