Menstria · reference
Every abnormality, properly named.
Menstrual problems are described with terminology that changed substantially in 2011 and again in 2018 — and much of the older vocabulary is still in circulation, including in consultation rooms. This page gives the current name for each abnormality, what it means, and which ones need evaluation rather than reassurance.
Two things are being described here, and they are not the same. An abnormality of the period is about the bleeding itself — how much, how long, when else. An abnormality of the cycle is about the process that produces it — whether ovulation happened, and when. Most bleeding problems are downstream of a cycle problem.
Do not use this page to decide whether to wait. Seek care now if:
- you are soaking through a pad or tampon every hour for two hours in a row;
- you feel faint, dizzy or breathless, or your heart is racing;
- you are pregnant, or might be, and you are bleeding;
- you have any bleeding after menopause — even one episode, even spotting.
Searchable glossary
The terms
Search for a word you have heard, or filter by category. Each entry gives the medical name and what it actually means.
Filter by category or search across terms, abbreviations and definitions. Retired terminology is included and marked, since patients still arrive using it.
Where a Menstria tool assesses a term directly, the entry carries a link to it.
Abnormalities of the period
How bleeding itself is described
FIGO System 1 describes bleeding along four independent axes — frequency, duration, regularity and volume — plus bleeding that occurs outside the period altogether. The point of separating them is that a woman can be abnormal on one axis and entirely normal on the other three, and the combination narrows the cause considerably.
| Axis | Normal | Abnormal — current term |
|---|---|---|
| Frequency | 24–38 days | Under 24 days: frequent menstrual bleeding Over 38 days: infrequent menstrual bleeding No bleeding for 6 months: amenorrhea |
| Duration | 8 days or fewer | Over 8 days: prolonged menstrual bleeding |
| Regularity | Shortest to longest cycle varies by 7 days or less (ages 26–41), or 9 days or less (ages 18–25 and 42–45) | Greater variation: irregular menstrual bleeding |
| Volume | Not excessive by the patient's own judgment | Heavy menstrual bleeding · light menstrual bleeding |
| Outside the period | None | Intermenstrual bleeding (cyclic or random) · postcoital bleeding · unscheduled bleeding on hormonal therapy · postmenopausal bleeding |
FIGO System 1: Munro MG, Critchley HOD, Fraser IS. Int J Gynaecol Obstet. 2018;143(3):393–408.
Words that were retired
FIGO deliberately abandoned a set of terms because they were used inconsistently, often meant different things to different clinicians, and mixed description with implied cause. If you have been given one of these, it is not wrong — it is simply no longer the standard.
| Retired term | What it used to mean | Say instead |
|---|---|---|
| Menorrhagia | Heavy or prolonged periods, variously defined | Heavy menstrual bleeding, and/or prolonged menstrual bleeding — stated separately |
| Metrorrhagia | Bleeding between periods | Intermenstrual bleeding |
| Menometrorrhagia | Both of the above at once | Name each finding on its own axis |
| Polymenorrhea | Cycles that come too often | Frequent menstrual bleeding |
| Oligomenorrhea | Cycles that come too seldom | Infrequent menstrual bleeding — note the term persists in endocrine and PCOS literature |
| Dysfunctional uterine bleeding (DUB) | Abnormal bleeding with no structural cause found | Nothing — the concept is replaced by naming the actual PALM-COEIN category, usually AUB-O, AUB-E or AUB-C |
Terminology retirement per FIGO Systems 1 and 2: Munro MG, et al. Int J Gynaecol Obstet. 2018;143(3):393–408; Jain V, Munro MG, Critchley HOD. Int J Gynecol Obstet. 2023;162(Suppl 2):29–42.
Why this matters to you. "Menorrhagia" told a doctor that something was too much, but not whether it was volume or duration, and not why. The newer terms force each part of the problem to be stated separately — which is what makes it possible to work out the cause instead of just treating the bleeding.
Why this matters clinically. The retired vocabulary conflated symptom axes and, in the case of DUB, encoded a diagnosis of exclusion that was never operationalised. System 1 forces axis-specific description; System 2 then assigns cause. A patient may carry several System 1 descriptors and more than one PALM-COEIN category simultaneously, and the notation accommodates that.
Abnormalities of cause
PALM-COEIN — why the bleeding is happening
Once bleeding has been described, FIGO System 2 classifies the cause into nine categories. The split is deliberate: PALM causes are structural — you can see them on imaging or under a microscope. COEIN causes are not structural. More than one can be present at once, and finding a fibroid does not prove the fibroid is the reason.
| Code | Category | What it is |
|---|---|---|
| AUB-P | Polyp | A benign overgrowth of the uterine lining projecting into the cavity. Typically causes bleeding between periods rather than heavier periods. |
| AUB-A | Adenomyosis | Endometrial tissue growing within the muscular wall of the uterus. Classically heavy and painful periods, with an enlarged tender uterus. For the pain side, see the Period Pain Navigator; for the bleeding side, How Heavy Is Heavy? |
| AUB-L | Leiomyoma (fibroid) | Benign muscle tumours. Subclassified by position, because it is the ones distorting the cavity — submucosal — that bleed, not the ones sitting on the outside. |
| AUB-M | Malignancy & hyperplasia | Endometrial hyperplasia and cancer. Uncommon overall but the category that must be excluded first in the wrong age group or risk profile. |
| AUB-C | Coagulopathy | An inherited or acquired bleeding disorder. Frequently missed — the periods have always been heavy, so they were never treated as abnormal. |
| AUB-O | Ovulatory dysfunction | Ovulation absent or erratic, so there is no progesterone withdrawal to time the bleeding. What appears instead is estrogen breakthrough or withdrawal bleeding — unpredictable in timing and often in volume. The single largest category, and the one carrying hyperplasia risk with chronicity. Now further classified by HyPO-P (below). |
| AUB-E | Endometrial | A primary disorder of the endometrium's own local haemostasis or repair, with ovulation normal and no structural lesion. A diagnosis of exclusion — no confirmatory test exists in routine practice. |
| AUB-I | Iatrogenic | Caused by treatment: hormonal contraception, an intrauterine device, anticoagulants, and other agents affecting ovulation or haemostasis. Note that the scheduled bleed in a hormone-free interval is withdrawal bleeding from a paused drug, not menstruation, and unscheduled bleeding on continuous progestogen comes from a suppressed, atrophic lining. |
| AUB-N | Not otherwise classified | Rare or poorly characterised entities that fit nowhere else — arteriovenous malformation, myometrial hypertrophy, caesarean scar defect. |
FIGO System 2 (PALM-COEIN): Munro MG, Critchley HOD, Fraser IS. Int J Gynaecol Obstet. 2018;143(3):393–408.
The category most often missed
AUB-C deserves separate mention. Across studies of women with heavy menstrual bleeding, von Willebrand disease has been reported in roughly 5% to 24%, with a pooled estimate around 13% — far higher than in the general population, where the clinically apparent prevalence is on the order of 1 in 1,000. ACOG has recommended screening adolescents presenting with severe heavy menstrual bleeding for more than a decade, and screening rates in practice remain low.
The reason it gets missed is simple: if your periods have been heavy since they started, you have no personal baseline for "normal," so neither you nor anyone else flags it. Heavy periods from the very first one, easy bruising, frequent nosebleeds, bleeding after dental work, or a family member with the same pattern — any of these is worth mentioning explicitly.Heavy menstrual bleeding since menarche is the discriminating historical feature. Combine it with a structured bleeding assessment tool, epistaxis, gingival or post-procedural bleeding, or family history, and screen — CBC with platelets, PT/aPTT, fibrinogen, ferritin, and von Willebrand panel with factor VIII activity, timed away from oestrogen exposure and acute-phase states where possible.
VWD prevalence range and pooled estimate: systematic review data summarised in the AUB-C literature; ACOG guidance on von Willebrand disease in women. Both entries flagged for re-verification on the references page.
Abnormalities of the cycle
Ovulatory disorders
This is where the cycle-versus-period distinction becomes practical. If ovulation does not happen, there is no corpus luteum; without a corpus luteum there is no progesterone; without progesterone the endometrium keeps thickening under unopposed estrogen until it breaks down unpredictably. The result is bleeding at random intervals, sometimes very heavy, sometimes absent for months — and, over years, an increased risk of endometrial hyperplasia.
The distinction that most sources skip. Bleeding in an anovulatory cycle is not a period. A period is progesterone withdrawal bleeding, and without ovulation there is no progesterone to withdraw. What happens instead is either estrogen breakthrough bleeding — the lining proliferating under unopposed estrogen until it outgrows its support and breaks down — or estrogen withdrawal bleeding, when a follicle develops, fails to ovulate, and then regresses.
This is not pedantry. It is the reason anovulatory bleeding is unpredictable in timing rather than merely irregular, the reason it can be far heavier than a true period, and the reason chronic anovulation carries a hyperplasia risk that ordinary heavy periods do not. Calling both of them "periods" hides all three facts.
FIGO replaced the fifty-year-old WHO classification in 2022 with a system organised by anatomical level, remembered as HyPO-P.
| Type | Level | Typical examples |
|---|---|---|
| Type I | Hypothalamic | Functional hypothalamic amenorrhea from energy deficit, excessive exercise or psychological stress; congenital GnRH deficiency; infiltrative or neoplastic lesions. |
| Type II | Pituitary | Hyperprolactinemia, including prolactinoma and drug-induced; other pituitary tumours; Sheehan syndrome. |
| Type III | Ovarian | Premature ovarian insufficiency; iatrogenic causes including chemotherapy, radiotherapy and surgery; genetic causes. |
| Type IV | PCOS | Kept separate because its pathophysiology is multifactorial and does not sit at one anatomical level. |
FIGO Ovulatory Disorders Classification System: Munro MG, Balen AH, Cho S, et al. Int J Gynecol Obstet. 2022;159(1):1–20. Types I–III are subclassified at a second level by the mnemonic GAIN-FIT-PIE (Genetic, Autoimmune, Iatrogenic, Neoplasm; Functional, Infectious and Inflammatory, Trauma and vascular; Physiological, Idiopathic, Endocrine).
Two that are commonly mislabelled
PCOS is diagnosed in adults by the Rotterdam framework as updated in the 2023 international guideline: two of three from clinical or biochemical hyperandrogenism, ovulatory dysfunction, and polycystic ovary morphology — with the 2023 change that AMH may now substitute for ultrasound in adults only. Where irregular cycles and hyperandrogenism are both present, neither ultrasound nor AMH is needed. In adolescents both hyperandrogenism and ovulatory dysfunction are required, and neither ultrasound nor AMH should be used, because normal pubertal physiology overlaps too heavily; morphology is not assessed until eight years past menarche.
Premature ovarian insufficiency is not early menopause, and the distinction is not pedantic — ovarian function in POI fluctuates and can return intermittently, so spontaneous ovulation and pregnancy remain possible. ESHRE criteria are oligomenorrhea or amenorrhea for at least four months before age 40, with FSH above 25 IU/L on two occasions more than four weeks apart. Note the threshold divergence: NICE uses 30 IU/L and the older POF literature 40 IU/L; ESHRE's lower cut-off is intended to capture autoimmune cases that present with less markedly elevated FSH.
About FSH tests. A single blood test is a poor way to answer "am I in perimenopause." FSH swings widely from cycle to cycle during the transition, so a normal result does not rule it out and a high one does not confirm it. Your pattern of cycles over time is the better evidence — which is what the staging tool on this site uses.
On FSH in the transition. Cycle-to-cycle FSH variability across the menopausal transition limits the value of isolated measurement in women still menstruating; STRAW+10 stages on bleeding criteria for precisely this reason. Reserve FSH for the settings where it changes management — suspected POI, hysterectomy without oophorectomy, and ambiguity under age 45.
Pain and premenstrual
When the problem is not the bleeding
Painful periods and premenstrual mood disturbance are separate axes again — a cycle can be perfectly regular, normal in volume and duration, and still be disabling.
Dysmenorrhea
Primary dysmenorrhea is period pain with no underlying pelvic pathology, driven by prostaglandin-mediated uterine contraction. It typically begins within the first year or two after menarche, once cycles become ovulatory, starts with or just before the bleeding, and lasts one to three days.
Secondary dysmenorrhea is period pain caused by identifiable pathology — most often endometriosis or adenomyosis, also fibroids, pelvic inflammatory disease, and obstructive anomalies of the reproductive tract. The historical features that point to it: pain that began years after menarche rather than at the outset, pain that has been worsening, pain extending beyond the days of bleeding, deep pain with intercourse, and pain with bowel movements during the period.
One thing is worth stating plainly, because it is the most common reason for delay: period pain that stops you functioning is not something to be endured as normal. Pain that keeps you from school or work, that does not respond to over-the-counter anti-inflammatories taken properly, or that makes you vomit is a reason to be assessed — not a low pain threshold. The Period Pain Navigator works through exactly these features and tells you which of four situations you are in.Diagnostic delay in endometriosis remains measured in years, and the dominant contributor is normalisation of pain by patients, families and clinicians. Failure of adequate NSAID therapy, absenteeism, dyspareunia, dyschezia or cyclical bowel or urinary symptoms warrant evaluation; empirical treatment is reasonable, but laparoscopy is no longer required to make a working diagnosis before initiating it. The Period Pain Navigator applies the ACOG 3-to-6-month review interval and the ESHRE 2022 diagnostic pathway.
Premenstrual disorders
Premenstrual syndrome (PMS) is physical and mood symptoms in the luteal phase that resolve with or shortly after the onset of bleeding, and that are absent in the follicular phase. That symptom-free interval is the defining feature — symptoms present all month are not PMS.
Premenstrual dysphoric disorder (PMDD) is the severe form, and it is a distinct diagnosis rather than a matter of degree, with mood symptoms — marked lability, irritability or anger, depressed mood, anxiety — causing significant impairment. Diagnosing it properly requires tracking symptoms daily across at least two cycles, because recall alone is unreliable; roughly half the women who report the pattern do not show it once it is charted prospectively.DSM-5 requires prospective daily ratings over at least two symptomatic cycles for confirmation; retrospective report substantially over-identifies. Timing, not symptom content, distinguishes PMDD from premenstrual exacerbation of an underlying mood or anxiety disorder — the latter does not remit in the follicular phase, and the management differs.
By life stage
The same finding means different things at different ages
Adolescence
Irregular cycles in the first year or two after menarche represent normal maturation of the hypothalamic–pituitary–ovarian axis, not a disorder. Cycles in the years after menarche are commonly longer than adult cycles, and the widely used adolescent thresholds are: any single cycle over 90 days beyond the first year; cycles under 21 or over 45 days from one to three years post-menarche; cycles under 21 or over 35 days beyond three years. Primary amenorrhea — no period by age 15, or more than three years after breast development began — requires evaluation.
The abnormality that must not be dismissed at this age is heavy bleeding from the very first period, which is the classic presentation of an undiagnosed bleeding disorder.
The puberty sequence, the thelarche-to-menarche interval, what the first period is actually like, and the full list of findings that need checking are covered on the menarche page.
Reproductive years
Here the priorities are pregnancy (test first, always, including in women who believe they cannot be pregnant), then structural causes and ovulatory dysfunction. New intermenstrual or postcoital bleeding warrants cervical assessment regardless of screening history.
Perimenopause
Cycle change is expected — that is what the transition is. What is not expected, and what still requires evaluation rather than attribution to "just perimenopause": bleeding heavy enough to cause anaemia or flooding, bleeding between periods, and any cycle that has become both irregular and much heavier. Anovulatory cycles in this window mean prolonged unopposed estrogen exposure, which is precisely the setting in which endometrial hyperplasia develops.
After menopause
Any bleeding after menopause is abnormal. One episode. Spotting counts. In a meta-analysis of 129 studies, postmenopausal bleeding was present in about 91% of women with endometrial cancer, while about 9% of women presenting with postmenopausal bleeding were found to have endometrial cancer — approximately 7% among hormone therapy users and 12% when hormone therapy users were excluded.
Read those two numbers together. Nine out of ten women with postmenopausal bleeding will not have cancer, so this is not a reason to panic. But nine out of ten women who do have endometrial cancer are found because of exactly this symptom — which is why it is always investigated, and why it is investigated promptly.The complementary framing matters for counselling: high sensitivity of PMB as a presenting symptom for endometrial carcinoma, with a pre-test probability of roughly 9% that supports universal evaluation while permitting realistic risk communication. Risk stratification by hormone therapy exposure and geography accounted for significant heterogeneity in the pooled estimate.
Clarke MA, Long BJ, Del Mar Morillo A, Arbyn M, Bakkum-Gamez JN, Wentzensen N. JAMA Intern Med. 2018;178(9):1210–1222.
Bleeding on menopausal hormone therapy is a separate situation. Unscheduled bleeding in the first months of a continuous combined regimen is common and often settles; bleeding that starts after a period of amenorrhea on stable therapy, or that persists, is investigated the same way as any postmenopausal bleeding.
Where to go next
To put numbers on your own pattern: Cycle Length & Regularity Calculator if you have your period dates, Is My Cycle Normal? if you do not, How Heavy Is Heavy? for volume, Period Pain Navigator if the problem is pain rather than bleeding, and Perimenopause Stage Finder for STRAW+10 staging. Full source list on the references page.
None of this diagnoses anything. Naming a pattern correctly is the beginning of an evaluation, not a substitute for one.