Endometriosis classification, staging and reporting systems: a review on the road to a universally accepted endometriosis classification

N Vermeulen, International Working Group of AAGL, ESGE, ESHRE and WES, M S Abrao, J I Einarsson, A W Horne, N P Johnson, T T M Lee, S Missmer, J Petrozza, C Tomassetti, K T Zondervan, G Grimbizis, R L De Wilde
Facts, views & vision in ObGyn · 2021 · vol. 13(4) , pp. 305–330 · doi:10.52054/fvvo.13.3.025 · PMID:34672508 · W3207836880
article OA: bronze CC0 ⤵ 20 in-corpus citations
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⚙ AI-generated summary by claude@2026-06, 2026-06-08 ⓘ

This review identified 22 endometriosis classification systems published between 1973 and 2021, finding no international agreement and limited validation of most systems for correlation with patient outcomes.

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⚙ AI-generated deep summary by claude@2026-06, 2026-06-09 ⓘ

This paper is a systematic review that examined published endometriosis classification, staging, and reporting systems from 1973 to 2021, using a PubMed search with extracted and summarized data from the literature. The review identified 22 different systems created for varied purposes, but found that international agreement on how to describe endometriosis is lacking. It reports that only a subset of systems has been evaluated in studies matching their intended purpose, with a general scarcity of validation showing correlation with pain symptoms or quality of life, though some studies support the Enzian system for describing deep endometriosis surgically and confirm the endometriosis fertility index for infertility-related use. This paper is centrally about endometriosis — it reviews classification, staging, and reporting systems and evaluates how well they have been validated for clinical outcomes.

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Abstract

BACKGROUND: In the field of endometriosis, several classification, staging and reporting systems have been developed. However, endometriosis classification, staging and reporting systems that have been published and validated for use in clinical practice have not been systematically reviewed up to now. OBJECTIVES: The aim of the current review is to provide a historical overview of these different systems based on an assessment of published studies. MATERIALS AND METHODS: A systematic Pubmed literature search was performed. Data were extracted and summarised. RESULTS: Twenty-two endometriosis classification, staging and reporting systems have been published between 1973 and 2021, each developed for specific and different purposes. There is still no international agreement on how to describe the disease. Studies evaluating different systems are summarised showing a discrepancy between the intended and the evaluated purpose, and a general lack of validation data confirming a correlation with pain symptoms or quality of life for any of the current systems. A few studies confirm the value of the Enzian system for surgical description of deep endometriosis. With regards to infertility, the endometriosis fertility index has been confirmed valid for its intended purpose. CONCLUSIONS: Of the 22 endometriosis classification, staging and reporting systems identified in this historical overview, only a few have been evaluated, in 46 studies, for the purpose for which they were developed. It can be concluded that there is no international agreement on how to describe endometriosis or how to classify it, and that most classification/staging systems show no or very little correlation with patient outcomes. WHAT IS NEW?: This overview of existing systems is a first step in working towards a universally accepted endometriosis classification.

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Outcome instruments

Enzian

Condition tags

endometriosisinfertility

Citation neighborhood

Papers in the corpus that this work cites (lower rings, blue) and that cite this one (upper rings, green). Dot size scales with the paper's in-corpus citation count — bigger dot = more influential within the endo/adeno field. Click a dot to open that paper. [ expand to 2 hops ] — adds papers reached through this work's immediate citers/citees. Heavier; up to 60 extra dots.

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europepmc
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License: CC0 · commercial use OK