Understand the 4 stages of endometriosis, how they're classified, and when surgery is recommended based on symptoms, severity, and fertility goals.
Endometriosis is classified based on the number, depth, and location of endometrial implants and adhesions—**not** directly on pain severity. The American Society for Reproductive Medicine (ASRM) ranks it from Stage I (minimal) to Stage IV (severe), using a point system.
🔬 ASRM Stages of Endometriosis
| Stage | Point Range | Description |
|---|---|---|
| I (Minimal) | 1–5 | Few superficial implants, little or no adhesions |
| II (Mild) | 6–15 | More implants, deeper; some adhesions |
| III (Moderate) | 16–40 | Many deep implants, endometriomas, filmy adhesions |
| IV (Severe) | >40 | Extensive deep implants, large cysts, dense adhesions |
🔍 Understanding the Differences
- Stage I–II: Minimal to mild; superficial lesions.
- Stage III: Moderate; deeper implants, small ovarian “chocolate cysts,” some scarring.
- Stage IV: Severe; deep implants, large ovarian cysts, dense adhesions, extensive scarring.
📌 Key Insights
- The ASRM point total helps surgeons predict the extent of disease and operative complexity, but it doesn’t necessarily reflect pain or infertility :contentReference[oaicite:2]{index=2}.
- The severity of symptoms can vary independently of the stage.
🧩 Alternative Classification by EndoFound
Endometriosis Foundation of America suggests a descriptive, location-based system:
- Category I: Peritoneal (superficial lesions)
- Category II: Ovarian endometriomas (“chocolate cysts”)
- Category III: Deep infiltrating endometriosis in pelvic organs
- Category IV: Extensive deep lesions reaching beyond pelvis :contentReference[oaicite:3]{index=3}.
🛠️ When Is Surgery Recommended?
Surgery is generally considered when:
- Pain is moderate to severe and doesn't respond to medications or hormonal therapies.
- There are endometriomas (especially large ovarian cysts).
- Infertility is an issue, and lesions are surgically accessible.
- Diagnostic laparoscopy is needed to confirm diagnosis.
The need for surgery depends on symptom severity, fertility desires, and treatment response—not solely on stage. For example, some women with Stage I–II may benefit from surgery if they have significant pain or infertility; others with advanced disease might manage well with medication and monitoring.
📋 Summary
- Endometriosis is staged I–IV by ASRM based on a scoring system.
- Symptom severity doesn’t always match the stage.
- Surgery is tailored to your symptoms, fertility goals, and response to other treatments.
Learn More
This classification helps doctors plan treatment but isn’t the only factor. Work with your gynecologist to find a personalised care plan that addresses your pain, fertility goals, and quality of life.