The FIGO Recommendations on Terminologies and Definitions for Normal and Abnormal Uterine Bleeding

Ian S. Fraser, M.D.; Hilary O.D. Critchley, M.D.; Michael Broder, M.D.; Malcolm G. Munro, M.D.


Semin Reprod Med. 2011;29(5):383-390. 

In This Article

Recommended Terminology, Definitions, and Classifications of Symptoms of Abnormal Uterine Bleeding

Disturbances of menstrual bleeding manifest in a wide range of presentations (Fig. 1 and Fig. 2A-D). AUB is the overarching term used to describe any departure from normal menstruation or from a normal menstrual cycle pattern. The key characteristics are regularity, frequency, heaviness of flow, and duration of flow, but each of these may exhibit considerable variability (Fig. 2A-D). Several abbreviations for these terminologies are established or becoming established by increasing popular usage (Table 2).

Figure 1.

The relationships of different types of symptoms and signs of abnormal uterine bleeding using recommended terminologies.

Figure 2.

(A–D) Schematic illustrations of four different menstrual cycle patterns and associated, objectively measured menstrual blood loss. These cycles illustrate the characteristics of each type of common pattern in the context of the new recommended terminologies. D1, D28 represent days of idealized cycles; MBL describes objectively measured menstrual blood loss.

Disturbances of Regularity

Irregular Menstrual Bleeding (IrregMB): Everyone understands when a menstrual cycle is irregular, but determining a definition is challenging. Using the published data from several population studies (2,3) gives a definition of >20 days in individual cycle lengths over a period of 1 year, which is the definition we prefer. A very detailed analysis of the largest single database gives a definition of "a range of varying lengths of bleeding-free intervals exceeding 17 days within one 90-day reference period."[2–3] These data include women of varying ages but with no known pathology or hormonal therapy. The databases undoubtedly include women with polycystic ovaries but no formal diagnosis of polycystic ovary syndrome.

Absent Menstrual Bleeding (Amenorrhea): No bleeding in a 90-day period (some authorities prefer to use a longer denominator). It is recommended that the term amenorrhea be retained because there is little controversy in its use or definition.

Disturbances of Frequency

Infrequent Menstrual Bleeding (Oligomenorrhea): One or two episodes in a 90-day period. It is recommended that the term oligomenorrhea be abolished.

Frequent menstrual bleeding: More than four episodes in a 90-day period (this term only includes frequent menstruation and not erratic intermenstrual bleeding; it is very uncommon).

Disturbances of Heaviness of Flow

Heavy Menstrual Bleeding (HMB): This is the most common clinical presentation of AUB. The term was first used in New Zealand National Guidelines on HMB.[14] It has been well defined in the routine clinical context on the basis of the patient's presenting complaint in the NICE Guidelines of the National Institute of Health and Clinical Excellence of the United Kingdom:[15] "HMB should be defined as excessive menstrual blood loss which interferes with the woman's physical, emotional, social and material quality of life, and which can occur alone or in combination with other symptoms." A corollary of this definition is that any interventions should aim to improve quality of life measures.

HMB also needs to be defined more objectively on a research basis as the measurement of actual blood loss per menstrual period, using the extraction of hemoglobin (alkaline hematin method) from menstrual sanitary supplies (pads and tampons, carefully collected after detailed counseling).[16–18] Clinicians and researchers also need to be aware that >50% of the total menstrual loss is an endometrial transudate and the whole blood component usually varies between 30% and 50%.[19] HMB is typically associated with a symptom complex, including variable pelvic pain and somatic symptoms.

Heavy and Prolonged Menstrual Bleeding (HPMB): This complaint is much less common than HMB on its own. The distinction from HMB is worth making because these two symptomatic components may have different etiologies and may respond differently to therapies.

Light Menstrual Bleeding: This is based on complaint by the patient, is only rarely related to pathology, and is usually a cultural complaint in those communities where a heavy, "red" bleed is valued as a perceived sign of health.

Disturbances of the Duration of Flow

Prolonged Menstrual Bleeding: Recommended to be used to describe menstrual periods that exceed 8 days in duration on a regular basis. This phenomenon is commonly associated with heavy menstrual bleeding ("heavy and prolonged menstrual bleeding" [HPMB]). This is much less common than HMB of normal duration.

Shortened Menstrual Bleeding: A very uncommon complaint and defined as menstrual bleeding of no longer than 2 days in duration. The bleeding is also usually light in volume and is uncommonly associated with serious pathology (such as intrauterine adhesions and endometrial tuberculosis)

Irregular Nonmenstrual Bleeding

Nonmenstrual bleeding is common and usually consists of the occasional episode of intermenstrual or postcoital bleeding associated with minor surface lesions of the genital tract, but such bleeding may herald more serious lesions such as cervical or endometrial cancer. Intermenstrual bleeding is defined as irregular episodes of bleeding, often light and short, occurring between otherwise fairly normal menstrual periods (Fig. 2). This bleeding may occasionally be prolonged or heavy, and it may occur on a regular basis around ovulation as a physiological event in 1–2% of cycles. Women with surface lesions of the genital tract may typically experience bleeding during or immediately after sexual intercourse (postcoital bleeding). The term acyclic bleeding is rarely used but encompasses those few women who present with totally erratic bleeding, with no discernable cyclic pattern, usually associated with fairly advanced cervical or endometrial cancer. Premenstrual and postmenstrual spotting (or staining) are descriptions of very light bleeding that may occur regularly for ≥1 days before or after the recognized menstrual period. These symptoms may be indicative of endometriosis or endometrial polyps or other structural lesions of the genital tract.

Bleeding Outside Reproductive Age

Precocious menstruation (occurring before 9 years of age) is uncommon and usually associated with other signs of precocious puberty. Postmenopausal bleeding (PMB) is common and usually defined as bleeding occurring >1 year after the acknowledged menopause. "The menopause" is the last natural menstrual period that a woman will experience and can only be determined in retrospect when a year of amenorrhea has followed it. PMB is an important symptom because of its common association with structural uterine pathology, including malignancy. The stages of the menopause transition and the occurrence of menopause are defined by the STRAW (Stages of Reproductive Aging Workshop) classification.[20]

Acute or Chronic Abnormal Uterine Bleeding8

It is proposed that acute AUB is "an episode of bleeding in a woman of reproductive age, who is not pregnant, that is of sufficient quantity to require immediate intervention to prevent further blood loss." Chronic AUB is "bleeding from the uterine corpus that is abnormal in duration, volume, and/or frequency and has been present for the majority of the last 6 months."

Patterns of Bleeding21

Sometimes called the "shape" of the volume of the bleeding pattern over the days of one menstrual period, this aspect of the menstrual bleeding experience of individual women is very poorly understood. Only one article has tried to define it in different populations.[21] It is greatly in need of future research in both normal and abnormal uterine bleeding. In general, in the normal cycle, it is recognized that ~90% of the total menstrual flow is lost within the first 3 days of menstruation, with day 1 or 2 the heaviest and day 4 and 5 very light (Fig. 2). However, in women with AUB, daily patterns of loss may be highly variable.

The Special Case of Disturbed Uterine Bleeding Patterns During Use of Reproductive Hormonal Therapies and Hormonal Contraception

Menstrual bleeding patterns are almost invariably modified by estrogen and/or progestogen therapies, sometimes in quite unpredictable ways. The least predictable patterns tend to come with use of the long-acting progestogen-only symptoms. New systems and terminologies had to be devised to define these new patterns.[18–23] The erratic nature and sometimes long intermenstrual intervals led to a need to use a longer timeline for each analysis, and a "reference period" of 90 days was selected as a sound compromise for the baseline. Twenty-eight or 30-day reference periods may still be used for monthly hormone systems. Description of the basic concepts of regularity, frequency, duration, and heaviness of flow is still necessary, but new terminologies were required (Table 3).[18] Heaviness of flow is difficult to assess with any degree of accuracy in routine clinical practice, and because most of the hormonal methods lighten the flow, it was decided the only distinction that could usually be made was between "bleeding" and "spotting," based on the need for sanitary napkin use. These terminologies allow for several different analyses within each reference period, which offer a useful degree of discrimination between different types of therapy. These analyses led to attempts to define clinically important bleeding patterns, derived initially from World Health Organization phase 3 clinical contraceptive trials[13] and subsequently modified after analysis of menstrual data from 1000 normal women (Table 4).[24]

Change in Menstrual Pattern

It needs to be recognized that most women experience episodes of considerable change in their menstrual pattern at different times in their lives. At times these patterns may become abnormal, and this change needs to be recognized as part of the presenting clinical problem.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.
Post as: