Menstrual Disorders Terminology and Patterns
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Direct answer
Menstrual disorders are deviations in how often a woman bleeds, how long bleeding lasts and how much blood she loses. A normal cycle runs 21 to 35 days with bleeding for two to seven days and a loss of up to about 80 mL, and each classical term marks a departure from one of these limits.
What you must remember
- Normal cycle: Cycle length of 21 to 35 days, duration of two to seven days and blood loss up to about 80 mL, the reference values for every term below.
- Menorrhagia: Excessive bleeding at regular intervals, classically defined by loss above 80 mL or duration beyond seven days.
- Metrorrhagia: Bleeding at irregular intervals that is unrelated to the menstrual cycle and may occur between periods.
- Polymenorrhoea: Cycles shorter than 21 days, so periods arrive too frequently.
- Oligomenorrhoea: Cycles longer than 35 days, so periods are infrequent but still occur.
- Hypomenorrhoea: Scanty bleeding of reduced volume or duration, with cycle timing that remains regular.
- Menometrorrhagia: Heavy and irregular bleeding combined, a pattern that prompts a search for structural or endometrial causes.
Reading the pattern, term by term
Each term describes one feature of the cycle, namely its interval, its duration or its volume. The table places the classical terms against the normal reference values, which is the comparison most exam vignettes expect the student to make.
| Term | Cycle interval | Bleeding pattern |
|---|---|---|
| Normal | 21 to 35 days | Two to seven days, up to about 80 mL |
| Menorrhagia | Regular | Over 80 mL or over seven days |
| Metrorrhagia | Irregular | Bleeding between periods |
| Polymenorrhoea | Under 21 days | Frequent periods |
| Oligomenorrhoea | Over 35 days | Infrequent periods |
| Hypomenorrhoea | Regular | Scanty, reduced volume or duration |
The FIGO terminology now prefers heavy menstrual bleeding and irregular bleeding, and its 2018 normal range is slightly wider (24 to 38 days), yet exam questions still use the classical terms. A woman can have more than one feature at once, so the history should record the interval, the duration and the volume separately before a term is chosen.
Where the exam tries to catch you
Vignettes often describe a symptom and expect the student to name the pattern precisely.
- Trap: Calling every heavy period menorrhagia without any measure. Correct: Menorrhagia is defined by loss or duration beyond normal limits, and clinicians usually judge it from the history of flooding, clots and anaemia.
- Trap: Confusing oligomenorrhoea with amenorrhoea. Correct: Oligomenorrhoea still has periods at intervals beyond 35 days, whereas amenorrhoea means no menstruation at all.
- Trap: Mixing up polymenorrhoea and polymenorrhagia. Correct: Polymenorrhoea means cycles under 21 days, whereas polymenorrhagia means frequent and heavy bleeding.
- Trap: Using metrorrhagia for any heavy bleeding. Correct: Metrorrhagia describes irregular timing, while heavy bleeding at regular intervals is menorrhagia.
Frequently asked questions
What is the normal menstrual cycle length in days?
A normal menstrual cycle lasts 21 to 35 days, counted from the first day of one bleed to the first day of the next. Cycles shorter than 21 days are polymenorrhoea, and cycles longer than 35 days are oligomenorrhoea.
How is menorrhagia defined in standard textbooks?
Menorrhagia is classically defined as blood loss above about 80 mL per cycle, or bleeding that lasts longer than seven days, at regular intervals. The newer FIGO term heavy menstrual bleeding describes the same clinical picture.
What is the difference between metrorrhagia and menorrhagia?
Metrorrhagia means bleeding at irregular intervals that is unrelated to the menstrual cycle. Menorrhagia means excessive bleeding that occurs at regular intervals, and the two can coexist as menometrorrhagia.
What does oligomenorrhoea mean in a menstrual history?
Oligomenorrhoea means infrequent periods, with cycles longer than 35 days but still occurring. It is distinct from amenorrhoea, in which menstruation does not occur at all.
Which term describes scanty menstrual bleeding?
Hypomenorrhoea describes scanty bleeding of reduced volume or duration while the cycle timing stays regular. It should not be confused with oligomenorrhoea, which concerns the interval between periods.