Beyond Coincidence: Endometriosis and Polyps

Not Just Coexistence: Endometriosis and Polyps Share a Twofold Risk Relationship

Key Points

Highlights: 

• Endometriosis and endometrial polyps show a bidirectional association, each condition approximately doubling the risk of the other. 
• The association is stronger in infertile women.

Importance:

• Concomitant endometrial polyps in women with endometriosis should not be overlooked, as they carry important implications for infertility evaluation and management.

What’s done here:

• This is a systematic review and meta-analysis of 22 observational studies (n ≈ 10,900).
• It evaluates the bidirectional association between endometriosis and endometrial polyps.
• Risk of endometrial polyps is assessed in women with endometriosis.
• Also risk of endometriosis is assessed in women with endometrial polyps.
• Subgroup analyses are performed according to infertility status and rASRM stage.

Key results:

• Women with endometriosis have an approximately twofold increased risk of endometrial polyps.
• Women with endometrial polyps have an approximately twofold increased risk of endometriosis.
• This bidirectional association remains significant in infertile populations.
• The association persists across disease stages, with a stronger effect in advanced disease.
• Women with stage III–IV endometriosis have a higher prevalence of endometrial polyps compared to those with stage I–II disease.

Limitations:

• Strengths are: large pooled sample size; bidirectional analysis of both conditions; subgroup analyses by infertility status and rASRM stage.
• Limitations are: low/very low certainty of evidence by GRADE; substantial heterogeneity across studies; predominance of infertile and Asian cohorts, limiting generalizability.

From the Editor-in-Chief – EndoNews

"This study addresses a clinically familiar but under-quantified observation: the coexistence of endometriosis and endometrial polyps. By demonstrating a bidirectional association with an approximate twofold risk in both directions, the authors provide a more structured perspective on what has often been considered incidental.

The strength of the analysis lies in its bidirectional design and its attempt to stratify by infertility and disease stage. These elements move the discussion beyond simple prevalence and toward clinically meaningful patterns. The observed gradient with increasing disease severity is particularly notable, although it should be interpreted with caution given the underlying heterogeneity.

At the same time, the limitations are substantial and cannot be overlooked. The evidence is derived entirely from observational studies, with significant heterogeneity and a predominance of infertility-based cohorts. This introduces a clear selection bias and limits generalizability to broader populations. In addition, the absence of standardized diagnostic criteria across studies raises concerns regarding consistency, particularly for both endometriosis staging and polyp detection.

Importantly, the findings should not be interpreted as evidence of causality or shared pathogenesis, but rather as a signal of frequent coexistence within a specific clinical context. The biological explanation remains speculative, and the study does not resolve whether this association reflects common mechanisms, detection bias, or overlapping patient populations.

From a clinical perspective, the relevance lies not in redefining disease mechanisms but in reinforcing awareness. The coexistence of intrauterine and extrauterine pathology may have implications for patient evaluation, particularly in infertility settings. However, any extension toward systematic screening or intervention strategies would be premature based on the current level of evidence.

In summary, this study contributes useful quantitative support to an already recognized clinical overlap. Its value lies in framing the association more clearly, while also highlighting the need for better-designed, prospective studies to determine its true significance."

Lay Summary

Endometriosis may not come alone.

A new study published in Reproductive Biomedicine Online by Dr. Paolo Viganò’s group from the Università degli Studi di Milano, Italy, highlights a clinically meaningful link between endometriosis and endometrial polyps—particularly in women with infertility.

Drawing on data from more than 10,000 women across 22 observational studies, the analysis shows that women with endometriosis are about twice as likely to have endometrial polyps.

The reverse is also observed: women diagnosed with polyps have a similarly increased likelihood of endometriosis, pointing to a bidirectional relationship between the two conditions.

This association appears even stronger in infertile women and in those with more advanced stages of endometriosis, suggesting that disease severity may play a role in this coexistence.

Rather than occurring independently, these findings support the idea that the two conditions frequently overlap in clinical practice.

Both endometriosis and endometrial polyps are estrogen-dependent and affect the uterine environment, which may partly explain why they are often found together.

While the study does not establish a direct causal relationship, it reinforces the importance of considering the broader reproductive context when evaluating patients.

Despite limitations in the quality of available evidence, the findings bring attention to a clinically relevant overlap that may influence how women with endometriosis—especially those facing infertility—are assessed and managed.

Research Source: https://pubmed.ncbi.nlm.nih.gov/41317651/