Overview
- Heavy menstrual bleeding (HMB) is defined as excessive menstrual blood loss that interferes with a woman's physical, social, emotional, or material quality of life.
- Historically defined by objective blood loss exceeding 80 mL per cycle, this quantitative threshold has been replaced by a patient-centred, symptom-based definition in contemporary practice.
- The FIGO PALM-COEIN classification system (introduced 2011, widely adopted) provides a structured framework for categorising AUB aetiology.
- It accepts that multiple causes may coexist and that structural lesions may be present in asymptomatic women.
- PALM causes are identified by imaging and histopathology; COEIN causes by history and targeted investigation.
PALM-COEIN Classification
Structural Causes (PALM)
| Category |
Key Features |
| P, Polyp (AUB-P) |
Common; incidence increases with age; causes intermenstrual and heavy bleeding; frequently coexists with fibroids; ~1.7% malignancy risk in premenopausal women with AUB; larger pedunculated polyps may undergo ischaemic necrosis |
| A, Adenomyosis (AUB-A) |
Endometrial glands and stroma within myometrium; associated with HMB and dysmenorrhoea; diffuse uterine enlargement; often coexists with endometriosis and fibroids; myometrial cysts are the most specific TVUS criterion; asymmetric myometrial thickening/heterogeneity and "Venetian blind" shadowing are suggestive |
| L, Leiomyoma (AUB-L) |
Submucosal and intramural subtypes most associated with HMB; mechanism involves disrupted haemostasis and vasoactive growth factor release; FIGO leiomyoma subclassification (types 0-8) defines cavity relationship |
| M, Malignancy and Hyperplasia (AUB-M) |
Endometrial carcinoma or hyperplasia; variable bleeding patterns (IMB, frequent, heavy, or prolonged); must be excluded in women ≥45, with risk factors, or with failed treatment |
Non-Structural Causes (COEIN)
| Category |
Key Features |
| C, Coagulopathy (AUB-C) |
Present in ~13% of women with HMB; von Willebrand disease is most common; suspect if HMB since menarche, family history of bleeding disorder, or personal history of epistaxis, easy bruising, minor wound bleeding, or oral/GI bleeding |
| O, Ovulatory Dysfunction (AUB-O) |
Anovulation → unopposed oestrogen → endometrial hyperplasia → erratic heavy bleeding; common at extremes of reproductive life (adolescence, perimenopause), PCOS, thyroid disorders, hyperprolactinaemia |
| E, Endometrial (AUB-E) |
Intrinsic endometrial haemostatic defects; excess vasodilators (PGE2, prostacyclin I2) or deficiency of vasoconstrictors (PGF2α, endothelin-1); abnormal fibrinolysis; diagnosis of exclusion in ovulatory women with structurally normal uterus |
| I, Iatrogenic (AUB-I) |
Exogenous hormones (COC, progestogens, HRT), anticoagulants, copper IUD; breakthrough bleeding in first 1-3 months of hormonal contraception occurs in 30-40% of users and is usually self-limiting |
| N, Not Yet Classified (AUB-N) |
Rare or poorly understood causes; includes chronic endometritis, arteriovenous malformations |
Clinical Assessment
Menstrual History
Document:
- Cycle frequency, regularity, and duration of flow
- Estimated blood loss: pad/tampon usage, flooding, clot passage
- Associated symptoms: dysmenorrhoea, IMB, postcoital bleeding, pelvic pressure
- Quality-of-life impact
- Contraceptive use and fertility intentions
- Personal and family history of bleeding diathesis
- Thyroid and other systemic symptoms
- Risk factors for endometrial pathology (obesity, PCOS, diabetes, tamoxifen use, Lynch syndrome family history)
Pictorial Blood Assessment Chart (PBAC)
The PBAC is a validated semiquantitative tool for estimating menstrual blood loss:
$$\text{PBAC score} = (\text{lightly soiled} \times 1) + (\text{moderately soiled} \times 5) + (\text{heavily soiled} \times 20) + (\text{small clots} \times 1) + (\text{large clots} \times 5)$$
- A PBAC score ≥100 per cycle correlates with objective blood loss >80 mL and supports the diagnosis of HMB.
- Useful for baseline documentation and monitoring treatment response.
Investigations
| Investigation |
Indication / Notes |
| Full blood count |
All women with HMB; assess for iron deficiency anaemia |
| Ferritin |
More sensitive marker of iron stores |
| TVUS |
First-line imaging; characterises uterine morphology, endometrial texture, adnexal pathology |
| Sonohysterography (SHG) |
Saline-infusion; superior to TVUS alone for intrauterine pathology (polyps, submucosal fibroids, adhesions); indicated when endometrium is irregular or poorly visualised on TVUS |
| Hysteroscopy |
Diagnostic and therapeutic; gold standard for intracavitary pathology |
| Endometrial biopsy |
Indicated: age ≥45; treatment failure; risk factors for endometrial cancer; persistent IMB; abnormal TVUS; erratic bleeding with obesity/PCOS/tamoxifen use. Outpatient Pipelle sensitivity ~90% for endometrial carcinoma. Avoid endometrial ablation without prior histological exclusion of hyperplasia/malignancy |
| Coagulation screen |
VWF antigen/activity, Factor VIII, ristocetin cofactor; indicated if personal/family bleeding history or HMB since menarche |
| TFTs, prolactin |
If ovulatory dysfunction suspected |
| Chlamydia PCR |
Consider with IMB, adolescents, or non-monogamous relationships |
| MRI pelvis |
Second-line; better characterisation of adenomyosis, multiple/large fibroids, surgical planning; not useful for endometrial polyp assessment |
Medical Management
First-Line Options
| Agent |
Mechanism |
Dose / Regimen |
Blood Loss Reduction |
Notes |
| LNG-IUS 52 mg |
Local progestogen → endometrial decidualisation and atrophy |
Intrauterine; licensed 5 years (evidence supports ≥7 years) |
75-96% reduction; approaches or equals ablation |
Most effective medical option; more cost-effective than other medical therapies and ablation; treats adenomyosis and hyperplasia without atypia; counsel about irregular spotting for first 3-6 months. The 13.5 mg LNG-IUS is not licensed for HMB treatment |
| Tranexamic acid |
Antifibrinolytic; inhibits endometrial fibrinolysis |
1 g orally three times daily during menstruation (up to 5 days) |
~50% reduction |
Non-hormonal; suitable for women wishing to conceive; contraindicated with personal history of thromboembolism |
| NSAIDs (mefenamic acid, ibuprofen) |
Inhibit prostaglandin synthesis; alter thromboxane A2/prostacyclin balance |
Mefenamic acid 500 mg or ibuprofen 400 mg three times daily during menstruation |
20-40% reduction |
Also relieves dysmenorrhoea; safe in women wishing to conceive; GI side effects possible |
| COCP |
Stabilises endometrium via combined oestrogen-progestogen |
Standard cyclical or continuous use |
~40-50% reduction |
Reduces dysmenorrhoea; added contraceptive benefit; contraindicated if oestrogen contraindications present |
| Cyclical norethisterone |
Progestogen → opposes oestrogen, stabilises endometrium |
5 mg three times daily, days 5-26 of cycle (21-day course) for ovulatory HMB |
Effective for ovulatory HMB |
Shorter courses (14 days, e.g. days 15-26) are only appropriate for anovulatory cycles; ineffective for ovulatory HMB if given for fewer than 21 days per cycle |
Second-Line Options
| Agent |
Mechanism |
Notes |
| GnRH agonist + add-back therapy (e.g. leuprorelin, goserelin) |
Pituitary downregulation → hypo-oestrogenic state → amenorrhoea |
Use ≤6 months without add-back; add-back HRT (low-dose oestrogen-progestogen or tibolone) mandatory beyond 6 months to protect bone density; benefit does not persist after cessation; use as short-term bridge or preoperative adjunct |
| Depot medroxyprogesterone acetate (DMPA) |
Continuous progestogen → endometrial atrophy; amenorrhoea in many |
Alternative when LNG-IUS not tolerated; unpredictable unscheduled bleeding in some |
Preoperative use of GnRH agonists:
- Correct anaemia before surgery
- Reduce uterine/fibroid volume to facilitate hysteroscopic resection or laparoscopic myomectomy
- Shrink fibroids before hysterectomy
Special population, coagulopathy (VWD): Desmopressin at onset of menses is highly effective; tranexamic acid, COCP, and LNG-IUS also reduce blood loss; haematology co-management recommended.
Surgical Management
Endometrial Ablation
- Destroys the endometrium to reduce or eliminate menstrual loss.
- Second-generation (non-resectoscopic) techniques (microwave ablation, thermal balloon, NovaSure® impedance-controlled bipolar) are preferred over first-generation hysteroscopic techniques due to equivalent efficacy with improved safety and shorter operating time.
Patient Selection:
| Criteria |
Detail |
| Completed family |
Absolute requirement |
| HMB refractory to or unsuitable for medical therapy |
, |
| Normal or near-normal uterine cavity |
No significant submucosal fibroids causing major cavity distortion |
| Endometrial histology: hyperplasia and malignancy excluded |
Biopsy mandatory prior to ablation |
| No desire for future fertility |
Not a reliable contraceptive; pregnancy after ablation carries risk of placenta accreta spectrum |
Absolute Contraindications:
| Contraindication |
| Desire for future pregnancy |
| Current or suspected endometrial carcinoma or atypical hyperplasia |
| Active pelvic infection |
| Significant cavity-distorting submucosal fibroids |
| Uterine anomalies incompatible with device deployment |
| Previous classical (vertical) uterine incision (device-dependent) |
- Ablation does not adequately treat endometrial hyperplasia or malignancy and precludes adequate future endometrial surveillance.
- Patient satisfaction is high (~80%), but 20-30% of women ultimately require further intervention, including hysterectomy.
Myomectomy
Indicated for symptomatic fibroids with preserved fertility intent. Route depends on fibroid location, size, and number:
| Approach |
Indication |
| Hysteroscopic |
Submucosal fibroids (FIGO types 0, 1, 2); most effective for HMB from intracavitary fibroids |
| Laparoscopic |
Intramural or subserosal fibroids; appropriate for fibroids up to ~8-10 cm in experienced hands |
| Open (abdominal) |
Large, multiple, or complex fibroids; when laparoscopic approach not feasible |
- Myomectomy does not guarantee resolution of HMB if other contributing causes coexist.
- Fibroid recurrence occurs in ~20-30% within 5 years.
- LNG-IUS expulsion rates are higher with fibroids >3 cm (15.4%) versus <3 cm (6.3%).
Hysterectomy
- Definitive cure for HMB; highest long-term satisfaction rates.
- Reserve for women who have completed their family and have failed or declined medical and conservative surgical options, or where concurrent pathology (adenomyosis, large fibroids) makes conservative management inappropriate.
| Route |
Notes |
| Laparoscopic (total or subtotal) |
Preferred where feasible; reduced morbidity, shorter recovery |
| Vaginal |
Suitable when uterus mobile and not excessively enlarged |
| Abdominal (open) |
When other routes not possible (large uterus, adhesions, concurrent procedures) |
- Subtotal hysterectomy preserves the cervix (cervical screening must continue).
- Bilateral salpingo-oophorectomy is not routinely recommended in premenopausal women; requires specific indication and careful surgical menopause counselling.
Complications of Untreated HMB
- Iron deficiency anaemia (most common systemic complication)
- Impaired quality of life, social and occupational dysfunction
- Delayed diagnosis of underlying malignancy or coagulopathy
- Subfertility if underlying pathology is untreated
Counselling Points
- Validate the woman's experience; reassure that HMB is common and often does not indicate serious pathology
- Discuss the PBAC as a useful self-monitoring tool
- Present all treatment options (medical, hormonal, surgical) with efficacy, side effects, reversibility, and effect on fertility
- LNG-IUS: counsel about irregular spotting for up to 6 months; amenorrhoea is a common expected outcome and should be framed positively
- Endometrial ablation: not a contraceptive; pregnancy after ablation carries risk of placenta accreta spectrum, reliable contraception must be used
- Hysterectomy: irreversible but curative; discuss surgical risks (bladder/bowel injury, haemorrhage, VTE, anaesthetic risk); subtotal hysterectomy requires ongoing cervical screening
- Address fertility preferences explicitly before any surgical option
- Coagulopathy (especially VWD): desmopressin, tranexamic acid, LNG-IUS, and COCP are all effective; haematology co-management recommended
- Acknowledge cultural and personal values in shared decision-making
Medicolegal and Ethical Considerations
- Failure to investigate for malignancy is a significant medicolegal risk; endometrial biopsy is mandatory in women ≥45 or with risk factors before empirical medical treatment that may mask underlying pathology
- Endometrial ablation in undiagnosed hyperplasia or malignancy is a serious adverse outcome; histological exclusion prior to ablation is non-negotiable
- Informed consent for surgical procedures must include alternatives, success rates, and specific complications (e.g. haematometra post-ablation, risk of conversion to hysterectomy)
- Advise that ablation does not guarantee amenorrhoea and hysterectomy may still be required
- Documentation of failed treatments, investigations, and shared decision-making is essential
- Women who decline investigation or treatment retain that right; document counselling and advise regarding ongoing surveillance if endometrial pathology risk factors are present
- In adolescents with HMB: prioritise coagulopathy screening before attributing bleeding to anovulation; structural causes are uncommon in this age group; COEIN aetiologies predominate
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