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Understanding of abnormal uterine bleeding has been hampered by inconsistent use of terminology and a lack of classification of its causes, but expert bodies are tackling these problems




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The proliferation of terms to describe heavy menstrual bleeding sometimes seems never-ending. From “menometrorrhagia” to “uterine hemorrhage,” these terms pop up quickly and confuse discussion of one of the most widespread problems in gynecology.

Enter the International Federation of Gynecology and Obstetrics (FIGO), which decided to tackle the inconsistent terminology and lack of classification of causes of abnormal uterine bleeding (AUB) with an eye toward standardizing research, facilitating discussion, and informing management decisions.

In this article, I focus on three aspects of this effort:

  • FIGO’s revamping of terminology and classification
  • comparisons of outcomes of hysterectomy versus endometrial ablation and the levonorgestrel-releasing intrauterine system
  • guidelines on management of AUB related to ovulatory disorders and endometrial hemostatic dysfunction.

FIGO revamps nomenclature for abnormal uterine bleeding

Munro MG, Critchley HO, Fraser IS. The FIGO systems for nomenclature and classification of causes of abnormal uterine bleeding in the reproductive years: who needs them? Am J Obstet Gynecol. 2012;207(4):259–265.

As early as 2004, FIGO began a process to standardize the nomenclature for defining both normal and abnormal uterine bleeding in reproductive-aged women who are not pregnant.1 This process was a response to a lack of consistency and continuity in the design and interpretation of basic science and clinical investigation related to the problem of AUB. Inconsistent definitions of AUB, such as “menorrhagia,” “metrorrhagia,” and “dysfunctional uterine bleeding,” along with the absence of standard categorization of the causes of AUB, have led to confusion and difficulties in comparing clinical trials and in finding significant, relevant, and even meaningful correlations among investigations of AUB. Applying information from asynchronous and often incomplete investigations to evidence-based clinical practice then becomes a challenge for the gynecologist.

Munro and colleagues summarize the process by which FIGO developed both a nomenclature system and a classification system of the causes of AUB, which were formally adopted by FIGO in 2010 and endorsed in 2012 by the American College of Obstetricians and Gynecologists (ACOG).1-6 The arduous process led to:

  • a refined definition of chronic AUB
  • a new category called acute AUB
  • a method for describing the clinical dimensions of menstruation and the menstrual cycle according to the following parameters:
  • regularity of onset
  • frequency of onset
  • duration of menstrual flow
  • heaviness, or volume, of menstrual flow.

Wherever appropriate, the definitions of normal for these parameters were based on statistics from large population studies that used medians and 5th and 95th percentiles.

The term “heavy menstrual bleeding” (HMB) is used to describe a woman’s perception of increased menstrual volume, regardless of regularity, frequency, or duration. AUB is the overarching term to describe any departure from normal menstruation, as defined by the parameters listed above. A group of misleading terms commonly used to describe AUB were eliminated from the FIGO nomenclature system, including “dysfunctional uterine bleeding,” “menorrhagia,” “hypermenorrhea,” “menometrorrhagia,” “polymenorrhagia,” and “metrorrhagia.”

The causes of AUB are classified in nine categories that are arranged according to the acronym PALM-COEIN:

  • Polyp
  • Adenomyosis
  • Leiomyoma
  • Malignancy and hyperplasia
  • Coagulopathy
  • Ovulatory disorders
  • Endometrial dysfunction
  • Iatrogenic
  • Not otherwise classified.

Leiomyoma are subclassified as submucous or other, with tertiary subcategorization for intramural, subserosal, and transmural lesions

In general, the components of the PALM group are discrete (structural) entities that are measurable visually via imaging or histopathology, or both, while the COEI (of the COEIN group) includes women for whom the AUB is unrelated to structural abnormalities.

The classification system provides the infrastructure for a thorough investigative process and a means to characterize AUB for an individual who may have one or more potential causes or contributors. Such a comprehensive assessment allows the basic scientist to identify pure populations for tissue and molecular studies, the clinical scientist to identify potential confounders when defining populations for clinical investigation, and the clinician, educator, and trainee to consider the multidimensional nature of AUB where asymptomatic “red herrings” may coexist with otherwise invisible disorders of menstrual function.

The FIGO Menstrual Disorders Working Group anticipates that widespread, international acceptance of the recommended terms, definitions, and classification for AUB will lead to improved and more meaningful communication in clinical trials and published research and will enhance communication between health-care providers and patients, leading to better management of AUB.

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