Despite the new frankness in films, one of the things we have yet to see is the woman pulling away from her lover as she notes blood on the sheets, or blood on her partner. Bleeding after sex or “postcoital bleeding” (PCB) generates many questions from our readers here at WebMD. So even if Hollywood has not yet made a movie with a PCB scene, it seems important to address some of your questions about this topic.
- How common is bleeding after sex?
- What causes the bleeding in a non-pregnant woman?
How common is bleeding after sex?
In the largest review, including some 38 studies, the incidence of postcoital bleeding was reported to be around 5-6 %. Where information was available for specific GYN problems, women with HIV had incidences ranging from 5-32% and women with pelvic prolapse had a 3% incidence (Shapley, 2006).
What causes the bleeding in a non-pregnant woman?
Infections. 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). While bacterial vaginosis (BV) was classified as a significant finding in 5% (Khattab, 2005), or 6% (Alfhaily, 2010) of women with PCB, BV is not usually identified as a cause for vaginal bleeding.
The same infections (e.g., 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. Thus, an infection can increase the risks for breakthrough bleeding, especially among users of hormonal birth control (e.g., pills/EvraPatch/NuvaRing).
Fragile tissue on the face of the cervix. In some women there is a normal enlargement of the area of fragile 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.
Polyps. 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 up to 12.5% of bleeding after sex (Sahu, 2007). Fortunately, most cervical polyps of this type can be readily seen during a speculum exam. If a polyp can be seen, the GYN may be able to remove it during the exam.
Endometrial polyps, or uterine fibroids, can create a focus for unstable uterine lining. Polyps can best be visualized on a saline infused hysterogram. A regular ultrasound may indicate only an irregularly thickened lining in the area of a collection of polyps. By contrast, significant fibroids can usually be seen readily on an ultrasound.
Hormonal status. As anyone who has used hormonal forms of birth control (pill/patch/ring/shot) can attest, spotting and breakthrough bleeding are common side effects. Spotting and breakthrough bleeding can appear as PCB as the lining of the uterus destabilizes more easily. This can be caused by either a very thinned out lining, or a lining where patches are out of synch and shedding erratically. Women using postmenopausal hormone therapy can experience the same issues with spotting and PCB as younger women using hormonal birth control—for pretty much the same reasons. In one study of 137 women with PCB, about 35% were using some version of female hormone medications (Alfhaily, 2010).
Among young women who are not using birth control which suppress ovulations, spotting can signal ovulation. Spotting and PCB can appear at midcycle (e.g., around cycle day 14 if she has a 28 day cycle). The brief spike, then fall, in estrogen levels right before the egg is released can prompt small amounts of the uterine lining to be easily shed—sometimes even without intercourse.
There are many hormonal conditions which can prompt an overly thickened lining inside the uterus (e.g., polycystic ovarian syndrome (PCOS), low thyroid, obesity, use of tamoxifen, perimenopause). If a woman has a history of missed periods, her uterine lining may be very thickened. In that instance, spotting after sex can represent small amounts of the lining being shed off the top layer. A too thick lining can provide a setting for development of abnormal, precancerous cells. This is why women with PCB, and risk factors for a thickened lining, may be screened with a biopsy of the lining (“endometrial biopsy”).
Women who are postmenopausal, and not using any form of estrogen, may have PCB. In this scenario the vaginal tissues can become very thin and easily traumatized — even with the use of lubricants. Spotting, pain with intercourse, and a sensation of vaginal dryness would help identify this type of PCB.