Abnormal Uterine Bleeding (AUB)
AUB is an umbrella term describing any bleeding from the uterus that is abnormal in volume, regularity and/or timing.
AUB Types
AUB covers the following abnormal bleeding patterns:
- Heavy menstrual bleeding (old: menorrhagia): the subjective perception of excessive menstrual blood loss that interfers with physical, social, emotional and/or material quality of life
- Intermenstrual bleeding (old: metrorrhagia): bleeding that occurs between clearly defined, cyclic, and predictable menses
- Prolonged bleeding: menstrual bleeding that last longer than the normal duration
- Unpredictable, infrequent, or absent bleeding (amenorrhoea)
- Chronic AUB: if present for the majority of the past 6 months
- Acute AUB: a severe episode of heavy bleeding that requires immediate medical intervention to prevent further blood loss
Causes and Recognition
The PALM-COEIN classification system is used to categorise the causes.
Structural causes (PALM):
| Category | Cause | Description / key clinical clues |
|---|---|---|
| P | Polyp (cervical / endometrial) | Classically causes:
|
| A | Adenomyosis | Common in 40-50 y/o (perimenopausal) women
|
| L | Leiomyoma (fibroid) | Common in women of reproductive age
|
| M | Malignancy and hyperplasia | Mainly endometrial cancer and hyperplasia, which classically causes post-menopausal bleeding
Other gynaecological malignancies (e.g. cervical, ovarian) can also cause AUB |
Non-structural causes (COEIN):
| Category | Cause | Description / key clinical clues |
|---|---|---|
| C | Coagulopathy | Examples include: vWD, platelet disorders, thrombocytopaenia, haemophilia
|
| O | Ovulatory dysfunction | Examples include: PCOS, thyroid disorder, hyperprolactinaemia
Typical causes:
|
| E | Endometrial | Primary disorder of the endometrium causing abnormal bleeding despite regular ovulation and no structural lesion. |
| I | Iatrogenic | Causes include:
|
| N | Not yet classified | Rare or less well-defined causes that do not fit the other categories, such as
|