Toolkit
Five systems are in use, they measure different things, and only one of them looks at pain at all. Here is what each number is actually reporting.
Stage IV does not mean worst pain. Stage I does not mean mild pain. The main systems score anatomy — where disease was found, how big it was, how stuck things were. How much it hurts was never one of the inputs. If you have been told your stage was low and your pain therefore should be too, that was not a finding. It was a misreading of what the number is for.
revised American Society for Reproductive Medicine
What it looks like. A single stage, written I, II, III or IV — sometimes with a point score.
What it scores. Lesion size and location across the peritoneum, cul-de-sac, ovaries and tubes, plus adhesions. Points are added up to a maximum of 150.
What it cannot tell you. It is scored during surgery, so it can only ever describe what was found — never predict. It has no established power to predict surgical complexity, pain, or fertility outcome.
Does not measure pain
#Enzian classification
What it looks like. Letter-and-number codes such as A2, B1, C3, O, T or F.
What it scores. Deep infiltrating disease compartment by compartment, each graded 1 to 3 by size. The 2021 expansion added ovarian endometrioma, superficial peritoneal disease and adenomyosis, plus supplementary compartments for bladder, ureter and intestine.
What it cannot tell you. It is weak on mild and superficial disease, and it does not explicitly record whether the pouch of Douglas was obliterated. It assesses neither pain nor adhesions.
Does not measure pain
American Association of Gynecologic Laparoscopists 2021
What it looks like. A complexity level, 1 to 4.
What it scores. Four components — superficial peritoneal disease, endometrioma, deep disease and pelvic adhesions — summed into a score describing how difficult the operation is.
What it cannot tell you. It was built to describe operative difficulty, not disease impact. It may underestimate what someone is living with when symptoms are severe but the anatomic score is low. It does not explicitly cover the uterosacral ligaments or disease outside the pelvis.
Does not measure pain
Numerical Multi-Scoring System of Endometriosis
What it looks like. An overall "E-score" number, often alongside an ultrasound report.
What it scores. Cyst size, adhesions judged by the ultrasound sliding sign, uterine findings, rare-site lesions — and pain rated 0 to 10 across seven pelvic regions.
What it cannot tell you. It depends heavily on who performed the ultrasound and how thorough the pelvic exam was, and it has had limited external validation. It does not assess superficial peritoneal implants or whether the tubes are open.
Includes a pain score
American & Global College of Endometriosis Specialists (2026)
What it looks like. Three separate stage numbers reported side by side, one per component — for example A-II, G-III, E-I.
What it scores. Three independent components, each staged I (minimal) to IV (severe): adenomyosis (A), genital endometriosis (G), and extragenital endometriosis (E — meaning disease outside the reproductive organs). It is the only system that scores adenomyosis in the same framework, and the only one that keeps genital and extragenital disease as separate numbers instead of combining them into one.
What it cannot tell you. It is brand new — an expert consensus framework, not yet independently validated or in routine use. If your report does not use it, that is normal; most surgeons do not use it yet. A high stage in any one component does not by itself tell you your symptom severity, treatment need, or fertility outlook.
Source: Nezhat et al., J Clin Med 2026;15(8):2871.
Does not measure pain
Superficial disease is the easiest to miss, and the classification systems themselves are weakest there. "No endometriosis seen" and "normal pelvis" are also two different sentences — the first describes what the surgeon looked for, the second describes everything.
