Current evidence does not support human papillomavirus as a cause of endometriosis. A recent meta-analysis pooling available studies found no significant association between HPV infection and endometriosis risk, and the largest population-level study in U.S. women reached the same conclusion after adjusting for age, ethnicity, income, and reproductive history. Yet the question persists because smaller studies keep finding HPV DNA inside endometriosis tissue at rates that seem hard to ignore, and newer research suggests the virus may still matter for fertility outcomes even if it does not trigger the disease itself.
What the Individual Studies Actually Found
The research landscape here is genuinely confusing, because individual studies have produced dramatically different results depending on where they looked and how they tested.
On one side, several smaller studies have detected HPV DNA in endometriosis tissue at rates that look elevated. One study of ovarian endometriosis found high-risk HPV in about 26% of tissue samples from women with the condition versus roughly 10% of samples from women without it.1PubMed. Prevalence of high-risk human papillomavirus infection in women with ovarian endometriosis A cross-sectional study of 81 women with deep endometriosis found that about a quarter tested positive for HPV in pelvic or vaginal samples, with low-risk strains (HPV 6 and HPV 11) being the most common types detected.2PubMed Central. Correlation of High-Risk Human Papilloma Virus with Deep Endometriosis: A Cross-Sectional Study
On the other side, a national population-based study using data from thousands of U.S. women found that the overall rate of HPV infection in women with endometriosis was not meaningfully different from the rate in women without it, once researchers accounted for factors like age and number of deliveries.3Scientific Reports. Association of endometriosis with genital human papillomavirus infection in US women: a national population-based study And one earlier study that specifically looked for DNA viruses in endometriotic lesions found none at all, concluding that “these results do not point towards any evidence that endometriosis is caused by these viruses.”4PubMed. Low prevalence of DNA viruses in the human endometrium and endometriosis
So depending on which study you read, HPV is either suspiciously common in endometriosis tissue or not present at all. That contradiction is important to understand before drawing any conclusions.
The Pooled Evidence Points Against a Causal Link
When researchers combined the available data in a meta-analysis, the pooled results showed no significant association between HPV infection and endometriosis risk. This held true whether they looked at any HPV subtype or specifically at high-risk strains.5PubMed Central. The association between HPV infection and endometriosis: Risk and fertility outcomes That meta-analysis did note something interesting: HPV seemed to be more common in patients who already had endometriosis compared to the general population. But being more common in a group is not the same as causing the condition. People with endometriosis may simply have immune or tissue-environment characteristics that make HPV easier to detect or slower to clear, without the virus playing any role in how the disease starts.
The large U.S. population-based study reinforced this. After adjustment, the prevalence ratio for any HPV in women with endometriosis compared to those without was 0.84, with a confidence interval that crossed 1.0, meaning the difference could easily be due to chance. Among women with health insurance (a proxy for better healthcare access and screening), those with endometriosis actually trended toward lower HPV rates.3Scientific Reports. Association of endometriosis with genital human papillomavirus infection in US women: a national population-based study That finding is the opposite of what you would expect if HPV were driving endometriosis.
Why Detection Rates Vary So Much Between Studies
A big part of why these studies disagree comes down to how they test for HPV, and this is where the science gets genuinely messy. HPV detection in tissue samples depends heavily on both the DNA extraction method and the PCR assay used. Different extraction protocols applied to the same type of tissue can produce very different results, partly because the DNA in preserved tissue samples tends to be fragmented, and shorter DNA fragments are easier to amplify than longer ones.6Pathology – Research and Practice. Comparison of five protocols to extract DNA from paraffin-embedded tissues for the detection of human papillomavirus That means a study using one extraction method might miss HPV DNA that another study’s method would catch, or vice versa.
The PCR assays themselves also matter. Newer real-time PCR platforms can detect very small amounts of viral DNA with high sensitivity, but that same sensitivity can sometimes pick up trace contamination or fragments that do not represent an actual active infection.7Scientific Reports. Evaluation and validation of HPV real-time PCR assay for the detection of HPV DNA in oral cytobrush and FFPE samples When you are dealing with tissue from surgeries stored in paraffin blocks, the line between “HPV was genuinely infecting this tissue” and “we detected trace viral DNA that was incidental” can be very thin.
This methodological problem explains a lot of the conflicting data. Studies that found HPV in a quarter of endometriosis samples and studies that found zero HPV in endometriosis tissue are not necessarily contradicting each other about biology. They may be reflecting different sensitivities and specificities of their lab techniques. Until the field standardizes how it tests for HPV in these samples, the detection rate numbers are hard to compare directly.
HPV in Lesions Versus HPV as a Cause
Even in studies where HPV DNA was found in endometriosis tissue, that does not mean the virus caused the endometriosis. A systematic review looking at infections as potential cofactors in endometriosis found that endometriosis lesions had a specific microbial profile, with mollicutes detected in over half of samples and HPV in about 11%.8PubMed Central. Infection as a potential cofactor in the genetic-epigenetic pathophysiology of endometriosis: a systematic review But the same review also reported that HPV rates in control tissues from the same patients were actually higher than in the endometriosis lesions themselves. One study within that body of evidence found high-risk and medium-risk HPV in about 11% of endometriosis lesions but in roughly 28% of other pelvic tissues used as controls.9Fertility and Sterility. Correlation of high-risk human papilloma viruses but not of herpes viruses or Chlamydia trachomatis with endometriosis lesions If HPV were driving endometriosis, you would expect more virus in the diseased tissue, not less.
That pattern suggests HPV may be a bystander rather than a driver. The pelvic cavity is not a sterile environment, and various microbes can be detected there without necessarily causing disease. Endometriosis lesions create local inflammatory environments that could either attract or resist microbial colonization depending on the immune dynamics at play. Finding a virus in a tissue does not prove the virus put the tissue there. Every HPV-positive endometriosis patient in one of these studies also had a history of cervical HPV infection, which makes sense given how common HPV is in the general population.9Fertility and Sterility. Correlation of high-risk human papilloma viruses but not of herpes viruses or Chlamydia trachomatis with endometriosis lesions The virus may simply be present in some of the same tissues where endometriosis happens to grow.
Where HPV Might Actually Matter for Endometriosis Patients
The more clinically relevant finding is not about whether HPV causes endometriosis but about what happens when someone has both. The same meta-analysis that found no causal link also included a case-control analysis of fertility outcomes. Among endometriosis patients who underwent surgery, those who were HPV-positive had substantially lower postoperative live birth rates compared to HPV-negative patients. The difference was striking: roughly 11% live birth rates in the HPV-positive group versus about 21% in the HPV-negative group.5PubMed Central. The association between HPV infection and endometriosis: Risk and fertility outcomes
That finding, if it holds up in larger studies, has practical implications. Endometriosis already impairs fertility through inflammation, adhesions, and disrupted ovarian function. If HPV independently worsens those outcomes, then HPV screening and treatment could become part of the fertility workup for endometriosis patients planning surgery. Right now, this is based on limited data and needs replication, but it shifts the conversation from “Does HPV cause endometriosis?” toward “Does HPV affect how well we can treat endometriosis-related infertility?”
The mechanism is not fully worked out, but HPV is known to alter local immune function in tissues it infects. In the cervix, persistent HPV infection suppresses certain immune responses to avoid clearance. If similar immune suppression occurs in pelvic tissues, it could interfere with the healing and immune remodeling that happens after surgical removal of endometriosis. That is speculative at this point, but it offers a plausible reason why HPV-positive endometriosis patients might have worse reproductive outcomes without HPV being the cause of the disease itself.
The Reservoir Hypothesis
One emerging idea worth following is that endometriosis lesions could serve as reservoirs for HPV. Some researchers have proposed that ectopic endometrial tissue may harbor the virus in ways that make it harder for the immune system to clear.10PubMed Central. Delayed onset of HPV-associated uterine malignancies: seven pathogenetic factors in contrast to cervical cancer This is a subtler claim than saying HPV causes endometriosis. It suggests the relationship might run in the opposite direction: endometriosis creates tissue environments where HPV can persist, not the other way around.
If this hypothesis is correct, it could partly explain why some studies detect HPV more frequently in patients with endometriosis. The extra tissue provides more places for the virus to hide. It could also have implications for HPV-related cancer risk. The cervix is the best-studied site for HPV-driven malignancy, but HPV can also play a role in cancers of the endometrium and ovary in rare cases. Whether endometriosis tissue that harbors HPV faces any elevated transformation risk is genuinely unknown and would require long-term follow-up studies that have not been done. One reported case of an HPV-18-positive ovarian endometriosis that was also associated with ovarian cancer exists in the literature, but a single case cannot establish a trend.9Fertility and Sterility. Correlation of high-risk human papilloma viruses but not of herpes viruses or Chlamydia trachomatis with endometriosis lesions
Should You Worry About HPV If You Have Endometriosis?
Based on current evidence, HPV infection should not be treated as a risk factor for developing endometriosis. The meta-analysis and the large population-based data are consistent on this point: there is no meaningful increase in endometriosis risk associated with HPV. If you have been diagnosed with endometriosis, learning you also have HPV does not mean one caused the other. HPV is extraordinarily common, affecting most sexually active people at some point, and endometriosis affects roughly one in ten women of reproductive age. The two conditions will inevitably overlap in a large number of people by simple probability.
Where HPV status may be worth paying attention to is if you are planning surgery for endometriosis-related infertility. The preliminary data on reduced live birth rates in HPV-positive patients after surgery is not yet robust enough to change clinical guidelines, but it is something to discuss with a reproductive specialist. HPV vaccination remains worthwhile for its established benefits in preventing cervical, anal, and oropharyngeal cancers, and if future research confirms a fertility interaction, vaccination could carry an additional indirect benefit for people with endometriosis.
Microbes and Endometriosis Beyond HPV
HPV is just one thread in a larger conversation about whether infections contribute to endometriosis. The systematic review that examined microbial colonization of endometriosis lesions found a distinctive bacterial profile: mollicutes were present in over half of samples, and researchers also detected DNA with high similarity to Shigella species.8PubMed Central. Infection as a potential cofactor in the genetic-epigenetic pathophysiology of endometriosis: a systematic review These findings do not prove that bacteria cause endometriosis either, but they do suggest that lesions create their own local microbial ecosystem once they establish.
The broader question is whether any of these microbes act as cofactors, not causing endometriosis on their own but possibly influencing how it progresses or how severe it becomes. The immune environment within and around endometriosis lesions is chronically inflamed and immunologically altered, which is exactly the kind of environment where microbes can behave differently than they would in healthy tissue. Untangling cause from consequence in that kind of setting is extremely difficult, which is why the field has produced more questions than answers so far. What the research does make clear is that endometriosis is not a simple hormonal condition but one that involves complex interactions between tissue, immune function, and the local microbial environment. HPV fits into that picture as one of many organisms found at the scene, but not as a proven instigator.