Contemporary evaluation of women and girls with abnormal uterine bleeding: FIGO Systems 1 and 2

Abstract

Abnormal uterine bleeding (AUB) is common, often debilitating, and may affect over 50% of reproductive-aged women and girls. Whereas AUB is a collection of symptoms that include intermenstrual bleeding and abnormalities in period duration, cycle length, and regularity, it is heavy menstrual bleeding (HMB) that is most contributory to iron deficiency and related anemia. It is apparent that AUB, in general, and HMB, in particular, remain underrecognized and underreported. FIGO created two systems for assessing and classifying AUB. FIGO System 1 defines the bleeding pattern using four primary descriptors: frequency, duration, regularity, and flow volume. FIGO System 2 provides a structured classification system of possible causes of AUB, using the acronym PALM-COEIN. "PALM" refers to structural causes of AUB (Polyp, Adenomyosis, Leiomyoma, Malignancy), and "COEI" refers to nonstructural causes (Coagulopathy, Ovulatory dysfunction, Endometrial, and Iatrogenic). The "N" is reserved for those entities that are currently not otherwise classified. Using FIGO System 1 as a gateway to FIGO System 2 streamlines the investigation of reproductive-aged women and girls with AUB. Understanding the pathogenesis of the FIGO System 2 "PALM-COEIN" causes helps interpret investigations and the onward management of AUB. Numerous evidence gaps exist concerning AUB; however, if researchers and trialists universally adopt FIGO Systems 1 and 2 for the assessment and diagnosis of AUB, clear translatable research findings can be applied globally.

Keywords: abnormal uterine bleeding; heavy menstrual bleeding; iron deficiency; iron deficiency anemia.

FIGURE 1

FIGO Abnormal Uterine Bleeding (AUB) System 1, defining the nomenclature and definition of AUB (30). *The normal range is age dependent, with shortest to longest days for 18–25 years at ≤9 days, 26–41 years at ≤7 days, and 42–45 years at ≤9 days.

FIGURE 2

FIGO Abnormal Uterine Bleeding (AUB) System 2, describing the PALM‐COEIN Classification System for Causes of AUB in the Reproductive Years. Four categories define visually objective structural criteria (PALM: Polyp; Adenomyosis; Leiomyoma; and Malignancy and hyperplasia), four are nonstructural anomalies (COEI: Coagulopathy; Ovulatory dysfunction; Endometrial disorders; Iatrogenic causes), and one (N) is reserved for entities categorized as “Not otherwise classified.” The leiomyoma category (L) is subdivided into patients with at least one submucous myoma (LSM) and those with leiomyomas that do not impact the endometrial cavity (Lo).

FIGURE 3

FIGO subclassification system for leiomyomas. The system includes the tertiary classification of leiomyomas dependent on location. Classification of lesions that are transmural are categorized by their relationship to both the endometrial and the serosal surfaces. The endometrial relationship is noted first, with the serosal relationship second (e.g. Type 2–5). Leiomyomas that do not relate to the myometrium at all are classified as Type 8, and would include cervical lesions (demonstrated), those that exist in the round or broad ligaments without direct attachment to the uterus, and other so‐called “parasitic” lesions.

FIGURE 4

Typically, but not always, these disorders manifest abnormalities in FIGO System 1 parameters that describe menstrual bleeding pattern: frequency, regularity, duration and volume of bleeding., ,

FIGURE 5

The proposed FIGO classification system for ovulatory disorders., , This system allows for an initial allocation of presumed primary source of ovulatory dysfunction (i.e. hypothalamus, pituitary gland, or ovary). Polycystic ovary syndrome (PCOS) is defined separately and the WHO classification system for the same should be adopted. After anatomical allocation, known or presumed mechanism is classified according to the GAIN‐FIT‐PIE acronym, as appropriate and applicable.