Abnormalities
PALM-COEIN: why the bleeding is happening
3 min read
Once bleeding has been described, FIGO System 2 classifies the cause into nine categories. The split is deliberate: PALM causes are structural — you can see them on imaging or under a microscope. COEIN causes are not structural. More than one can be present at once, and finding a fibroid does not prove the fibroid is the reason.
| Code | Category | What it is |
|---|---|---|
| AUB-P | Polyp | A benign overgrowth of the uterine lining projecting into the cavity. Typically causes bleeding between periods rather than heavier periods. |
| AUB-A | Adenomyosis | Endometrial tissue growing within the muscular wall of the uterus. Classically heavy and painful periods, with an enlarged tender uterus. For the pain side, see the Period Pain Navigator; for the bleeding side, How Heavy Is Heavy? |
| AUB-L | Leiomyoma (fibroid) | Benign muscle tumours. Subclassified by position, because it is the ones distorting the cavity — submucosal — that bleed, not the ones sitting on the outside. |
| AUB-M | Malignancy & hyperplasia | Endometrial hyperplasia and cancer. Uncommon overall but the category that must be excluded first in the wrong age group or risk profile. |
| AUB-C | Coagulopathy | An inherited or acquired bleeding disorder. Frequently missed — the periods have always been heavy, so they were never treated as abnormal. |
| AUB-O | Ovulatory dysfunction | Ovulation absent or erratic, so there is no progesterone withdrawal to time the bleeding. What appears instead is estrogen breakthrough or withdrawal bleeding — unpredictable in timing and often in volume. The single largest category, and the one carrying hyperplasia risk with chronicity. Now further classified by HyPO-P (see ovulatory disorders). |
| AUB-E | Endometrial | A primary disorder of the endometrium's own local haemostasis or repair, with ovulation normal and no structural lesion. A diagnosis of exclusion — no confirmatory test exists in routine practice. |
| AUB-I | Iatrogenic | Caused by treatment: hormonal contraception, an intrauterine device, anticoagulants, and other agents affecting ovulation or haemostasis. Note that the scheduled bleed in a hormone-free interval is withdrawal bleeding from a paused drug, not menstruation, and unscheduled bleeding on continuous progestogen comes from a suppressed, atrophic lining. |
| AUB-N | Not otherwise classified | Rare or poorly characterised entities that fit nowhere else — arteriovenous malformation, myometrial hypertrophy, caesarean scar defect. |
FIGO System 2 (PALM-COEIN): Munro MG, Critchley HOD, Fraser IS. Int J Gynaecol Obstet. 2018;143(3):393–408.
The category most often missed
AUB-C deserves separate mention. Across studies of women with heavy menstrual bleeding, von Willebrand disease has been reported in roughly 5% to 24%, with a pooled estimate around 13% — far higher than in the general population, where the clinically apparent prevalence is on the order of 1 in 1,000. ACOG has recommended screening adolescents presenting with severe heavy menstrual bleeding for more than a decade, and screening rates in practice remain low.
The reason it gets missed is simple: if your periods have been heavy since they started, you have no personal baseline for "normal," so neither you nor anyone else flags it. Heavy periods from the very first one, easy bruising, frequent nosebleeds, bleeding after dental work, or a family member with the same pattern — any of these is worth mentioning explicitly.Heavy menstrual bleeding since menarche is the discriminating historical feature. Combine it with a structured bleeding assessment tool, epistaxis, gingival or post-procedural bleeding, or family history, and screen — CBC with platelets, PT/aPTT, fibrinogen, ferritin, and von Willebrand panel with factor VIII activity, timed away from oestrogen exposure and acute-phase states where possible.
VWD prevalence range and pooled estimate: systematic review data summarised in the AUB-C literature; ACOG guidance on von Willebrand disease in women. Both entries flagged for re-verification on the references page.