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PALM-COEIN Classification:
causes and treatment of HMB

HMB is a symptom which can be caused by several underlying medical conditions. In clinical practice there are several treatments that are used despite not being specifically approved for HMB. The following section is intended to give an overview of what is clinical practice. Please be aware that the label of a specific product may vary from country to country.

What challenges are there in identifying and classifying the underlying cause of heavy menstrual bleeding?

There is general inconsistency in the nomenclature used to describe abnormal uterine bleeding (AUB), as well as a lack of practical, objective methods to measure blood loss.1,2 Diagnosis is complex because there are many causes of AUB and individuals may have several potential causes simultaneously.1,3


What is needed is consistent, universally accepted terminology that can be used by clinicians, investigators, and patients to facilitate communication, clinical care, and research.4

The Menstrual Disorders Working Group was set up by the International Federation of Gynecology and Obstetrics (FIGO) to address these issues and to develop an agreed set of terms and definitions. The group developed a classification system – PALM-COEIN – which can be used to describe both structural and non-structural causes of AUB.

What is included in the PALM-COEIN classification?

PALM-COEIN consists of two parts.

The ‘PALM’ categories describe structural causes, which can be diagnosed by imaging and/or histopathological evaluation. The categories are: Polyp, Adenomyosis, Leiomyoma, and Malignancy and hyperplasia.

The ‘COEIN’ categories describe non-structural causes. Here, the patient’s medical history often provides a clue to diagnosis, even if their imaging results are normal. The categories are: Coagulopathy, Ovulatory dysfunction, Endometrial dysfunction, Iatrogenic, and Not otherwise classified.

Select the letter to get to the respective resources of the cause you are interested in.

P – Polyps

Benign growths on the lining of the uterus

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A – Adenomyosis

A condition in which the endometrium grows into the myometrium

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L – Leiomyoma

Also known as fibroids, leiomyoma are benign fibromuscular tumours of the myometrium

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M – Malignancy and hyperplasia

The irregular proliferation of the endometrial glands

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C – Coagulopathy

Several disorders of hemostasis can affect blood coagulation

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O – Ovulatory dysfunction

Abnormal, irregular or absent ovulation

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E – Endometrial dysfunction

Can include alterations in local production of vasoconstrictors, plasminogen activators or prostaglandins

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I – Iatrogenic

Bleeding caused by medical interventions or devices

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N – Not otherwise classified

Bleeding caused by conditions that are rare or which have an undetermined relationship to abnormal uterine bleeding symptoms

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PALM-COEIN Classification Infographic

A visual guide to the structural and non-structural causes of abnormal uterine bleeding and heavy menstrual bleeding with information on how to diagnose and treat them.



  1. Munro MG, et al. BJOG 2017;124:185–9.
  2. Liu Z, et al. Value Health 2007;10:183–94.
  3. Fraser I, et al. Int J Gynecol Obstet 2015;128:196–200.
  4. Munro MG, et al. Int J Gynaecol Obstet 2011;113:3–13.

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