15.5 The FIGO PALM-COEIN Classification of Abnormal Uterine Bleeding

The FIGO PALM-COEIN Classification for Abnormal Uterine Bleeding

In 2011 (and updated in 2018), FIGO discarded confusing historical terms such as "menorrhagia," "metrorrhagia," "oligomenorrhea," and "dysfunctional uterine bleeding (DUB)" in favor of standardized, descriptive terminology: Abnormal Uterine Bleeding (AUB), subclassified by the PALM-COEIN framework. The classification applies strictly to non-pregnant individuals of reproductive age.

FIGO PALM-COEIN Classification Framework
├── Structural Causes (PALM - Measurable by Imaging or Histopathology)
│   ├── P ──> Polyp (Endometrial or Cervical)
│   ├── A ──> Adenomyosis (Endometrial stroma/glands in myometrium)
│   ├── L ──> Leiomyoma (Uterine fibroids: Submucosal vs. Other)
│   └── M ──> Malignancy & Hyperplasia (Endometrial atypical hyperplasia/cancer)
└── Non-Structural Causes (COEIN - Not Characterized by Structural Lesions)
    ├── C ──> Coagulopathy (Systemic hemostatic disorders; e.g., vWD)
    ├── O ──> Ovulatory Dysfunction (Anovulation, irregular/unpredictable flow)
    ├── E ──> Endometrial (Primary local hemostatic or vasoconstrictive defect)
    ├── I ──> Iatrogenic (Exogenous hormones, IUDs, anticoagulants)
    └── N ──> Not Otherwise Classified (Rare or uncharacterized; e.g., AVMs)

Structural Etiologies (PALM)

Non-Structural Etiologies (COEIN)

• C - Coagulopathy (AUB-C): Systemic disorders of hemostasis. Von Willebrand disease (vWD) is the most common inherited bleeding disorder, present in up to 15% to 20% of adolescents presenting with severe heavy menses since menarche. Other causes include immune thrombocytopenia (ITP), platelet dysfunction, and liver failure.
  • ACOG Structured Screening Tool for Coagulopathy: Screen positive if (1) Heavy menstrual bleeding since menarche, PLUS (2) One of: history of postpartum hemorrhage, surgery-related bleeding, or dental work-associated bleeding, PLUS (3) Two or more of: bruising >1–2 times/month, epistaxis >1–2 times/month, frequent gum bleeding, or family history of bleeding disorders. If positive, order CBC, PT/INR, aPTT, von Willebrand factor (vWF) antigen, ristocetin cofactor activity, and factor VIII.
• O - Ovulatory Dysfunction (AUB-O): The most frequent cause of non-structural AUB in adolescents and perimenopausal individuals. In the absence of ovulation, no corpus luteum forms and no progesterone is secreted. The endometrium is subjected to continuous, chronic, unopposed estrogen stimulation, resulting in fragile, excessive vascular proliferation without structural stromal support. Eventually, the outgrown endometrium sloughs irregularly and incompletely, manifesting as unpredictable, non-cyclic bleeding that alternates between prolonged amenorrhea and massive, life-threatening hemorrhage.
  • Underlying Etiologies: Polycystic Ovary Syndrome (PCOS), perimenopausal HPO axis instability, hypothalamic dysfunction (extreme stress, anorexia, excessive athletic training), hyperprolactinemia, thyroid disease (both hypothyroidism and hyperthyroidism), and obesity (adipose tissue peripheral aromatization of androstenedione to estrone).
• E - Endometrial (AUB-E): Occurs in ovulatory individuals with completely normal cycle regularity and duration, but objectively heavy or prolonged menses without identifiable structural lesions. Caused by primary disturbances in local endometrial molecular hemostasis: deficiency in local vasoconstrictors (endothelin-1, prostaglandin F2α) and excess production of vasodilators (prostaglandin E2, prostacyclin), or accelerated endometrial lysis of fibrin clots due to elevated levels of endometrial tissue plasminogen activator (tPA).
• I - Iatrogenic (AUB-I): Unintended bleeding secondary to medical therapies: copper IUD (increased heavy menses and cramping), levonorgestrel IUD or subdermal etonogestrel implant (unscheduled breakthrough spotting, particularly in first 3–6 months), progestin-only pills (DMPA), systemic anticoagulants (warfarin, DOACs, heparin), psychotropics that elevate prolactin (antipsychotics, SSRIs), and herbal supplements (ginkgo, ginseng, garlic).
• N - Not Otherwise Classified (AUB-N): Rare or poorly understood conditions including uterine arteriovenous malformations (AVMs), myometrial hypertrophy, chronic endometritis, or isthmocele (cesarean scar defect/niche harboring trapped blood).