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Endometriosis Stages Infographic

The ASRM revised classification system (rASRM) divides endometriosis into four stages based on the location, depth, and extent of implants, endometriomas, and adhesions — scored during laparoscopic surgery by a surgeon.

Stage does NOT equal pain.Stage I (Minimal) can be severely debilitating, while Stage IV (Severe) can cause little to no pain. The rASRM score measures anatomical extent of disease — it does not predict your quality of life, fertility outcomes, or how much a treatment will help. This is one of the most important — and most commonly misunderstood — facts about endometriosis.
Endometriosis Stages I–IV — ASRM Classification InfographicA four-panel infographic illustrating the revised American Society for Reproductive Medicine (rASRM) staging system for endometriosis. Each panel shows a stylised cross-section of the pelvic anatomy with lesions, implants, adhesions, and endometriomas that correspond to that stage. Stage I (Minimal, score 1–5): a few superficial peritoneal implants. Stage II (Mild, 6–15): more implants, slightly deeper penetration, minimal adhesions. Stage III (Moderate, 16–40): many deep implants, small endometriomas (chocolate cysts) on ovaries, some filmy adhesions. Stage IV (Severe, above 40): extensive deep implants, large bilateral endometriomas, dense widespread adhesions.Endometriosis Stages — rASRM Classification156–151516–4040>40rASRM scoreStage IMinimal · Score 1–5Depth: superficial only• Few isolated implants• No adhesions• Ovaries unaffected• Peritoneal surface onlyrASRM: 1–5 ptsStage IIMild · Score 6–15Depth: superficial–moderate• More implants, deeper• Minimal/no adhesions• Possible ovary surface spots• Cul-de-sac may be involvedrASRM: 6–15 ptsStage IIIModerate · Score 16–40cystDepth: deep infiltrating• Many deep implants• Small endometrioma ≤3 cm• Filmy adhesions present• Cul-de-sac partial obliterationrASRM: 16–40 ptsStage IVSevere · Score >40cyst ≥3cmcystDepth: extensive, bilateral• Extensive deep implants• Large endometriomas ≥3 cm• Dense widespread adhesions• Complete cul-de-sac obliterationrASRM: >40 ptsendotracking.com · Educational only — not medical advice · Staging requires laparoscopic surgery by a specialist

The rASRM staging system scores endometriosis on a 1–150+ point scale based on the number, size, and depth of lesions found during laparoscopy. The four stages are cut-offs within that scale, not discrete disease types.

Stage Summary

StageNameScoreWhat it means anatomically
IMinimal1–5A few isolated superficial peritoneal implants; no adhesions; ovaries and tubes typically normal.
IIMild6–15More implants, some slightly deeper; minimal or no adhesions; cul-de-sac may be lightly involved.
IIIModerate16–40Many deep implants; small endometriomas (≤3 cm) on one or both ovaries; filmy adhesions present; partial cul-de-sac obliteration.
IVSevere>40Extensive deep implants; large bilateral endometriomas (≥3 cm); dense widespread adhesions; complete cul-de-sac obliteration possible.

Why stage doesn't equal pain — and why that matters

The biology

The rASRM score is an anatomical measure — it counts and sizes lesions visible to a surgeon through a laparoscope. Pain, by contrast, is driven by nerve sensitisation, inflammatory cytokine levels, and individual pain-processing differences that no score captures.

What this means for you

A Stage I diagnosis does not mean your pain is "minor." A Stage IV diagnosis does not mean you will suffer more than anyone else. If your symptoms are dismissed because of a low stage number, that is not good medicine. Symptom severity should drive treatment decisions alongside — not below — staging.

The only way to stage

Endometriosis staging requires diagnostic laparoscopy — a surgical procedure. Ultrasound and MRI can detect endometriomas and deep infiltrating disease but cannot assign a formal rASRM score. If you have not had surgery, you do not yet have an official stage.

For a deeper look at what staging means day-to-day, read our article:Understanding Endometriosis Stages. For living with symptoms at any stage, seeEndometriosis Pain Management Strategies.

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Track your symptoms across all stages

EndoTracking helps you log pain, symptoms, and cycles — and generate a doctor-ready PDF report before every appointment.

Available now on iPhone.