Heavy Menstrual Bleeding (Menorrhagia)

Introduction

Heavy menstrual bleeding (HMB), previously called menorrhagia, is excessive menstrual blood loss which interferes with quality of life. There may be other associated symptoms, depending on the underlying cause.

Previously, HMB was defined objectively by the volume of blood loss (>80ml). However, this definition is no longer used in clinical practice as menstrual blood loss is difficult to measure and did not consider individual patient factors.

HMB is a common presentation, both in general practice and gynaecology clinics.

Aetiology

HMB is a symptom of abnormal uterine bleeding (AUB). There are many causes of abnormal uterine bleeding, which can be categorised into structural and non-structural.

PALM-COEIN is a useful acronym to remember the structural and non-structural causes of abnormal uterine bleeding. Each of these causes can cause heavy menstrual bleeding.

It is not uncommon for no specific cause of heavy menstrual bleeding to be identified. Previously, these patients would have been labelled as having ‘dysfunctional uterine bleeding’ (DUB). However, this term is no longer used in current guidelines.

Risk factors

HMB is a symptom. Therefore, the risk factors for HMB depend on the underlying pathology. For example, risk factors for fibroids include increasing age and ethnicity (black and Asian women are at increased risk).

Clinical features

History

Heavy menstrual bleeding is a symptom, and patients may present with:

• Flooding
• Passage of clots
• Prolonged periods
• Fatigue and shortness of breath (if resulting anaemia)

Other symptoms will depend on the underlying cause of the HMB:

• Fibroids: painful periods
• Polyps: inter-menstrual bleeding, post-coital bleeding
• Malignancy (e.g. endometrial cancer): inter-menstrual bleeding, post-coital bleeding, post-menopausal bleeding
• Endometriosis and adenomyosis: pelvic pain

Important areas to cover in the history include:

• Cycle regularity and establishing if there is any inter-menstrual, post-coital bleeding or post-menopausal bleeding
• Past medical history: gynaecological history (including smears), co-morbidities, clotting disorders
• Drug history: anticoagulants, antiplatelets, tamoxifen (a risk factor for endometrial hyperplasia)
• Contraception: method and plans for future pregnancies as this may influence management

For more information, see the Geeky Medics guide to gynaecological history taking.

Clinical examination

Useful clinical examinations in the context of HMB include:

• Speculum examination
• Bimanual examination
• Vaginal swabs for sexually transmitted infections (in the context of irregular bleeding)
• Assessment for signs of anaemia (e.g. conjunctival pallor, koilonychia)
• Height, weight and BMI (helpful for identifying PCOS and other causes of anovulation)

Typical clinical findings will vary depending on the underlying cause of the HMB, for example:

• Cervical polyp: visible polyp protruding from the cervix
• Fibroids: bulky enlarged uterus on bimanual palpation
• Endometriosis: tender uterus on bimanual palpation
• Malignancy, pelvic inflammatory disease, cervical or endometrial polyps: abnormal vaginal discharge

Differential diagnoses

As discussed, HMB is a symptom rather than a diagnosis. All potential causes of HMB (outlined in aetiology) should be considered.

Investigations

Bedside investigations

Relevant bedside investigations include:

• Pregnancy test: all patients should have a pregnancy test performed if there is a risk of pregnancy (bleeding does not completely exclude pregnancy)

Laboratory investigations

Relevant laboratory investigations include:

• Full blood count (FBC): to identify anaemia
• Thyroid function tests (TFTs): to exclude an underlying thyroid disorder
• Coagulation profile: if there is clinical suspicion or a family history of a clotting disorder

Imaging

The most relevant imaging investigation for HMB is a transvaginal ultrasound scan.

This may identify structural causes such as polyps and fibroids. It also allows for assessing endometrial thickness – a thickened and heterogeneous appearance may suggest hyperplasia or malignancy.

In cases of suspected adenomyosis, other imaging modalities may be considered (e.g. MRI). However, a transvaginal ultrasound scan remains the first-line imaging investigation.

Interventional investigations

Interventional investigations may also serve a therapeutic purpose (see management).

Relevant investigations include:

• Hysteroscopy: to assess the endometrial cavity for structural abnormalities and macroscopic appearance of the endometrium
• Endometrial biopsy (only if indicated): to exclude atypical hyperplasia or endometrial malignancy

Indications for an endometrial biopsy may include:

• Thickened endometrium (seen on transvaginal ultrasound)
• Post-menopausal bleeding
• Women with HMB aged over 45
• Additional symptoms (e.g. inter-menstrual bleeding, short or irregular cycles)
• Presence of risk factors for endometrial hyperplasia or malignancy (e.g. obesity, anovulatory cycles in PCOS, women on tamoxifen)
• If medical treatment is not effective

NICE recommend a hysteroscopic directed biopsy to sample endometrial tissue. However, some units may perform blind endometrial sampling (using a Pipelle) in low-risk patients.

Management

Management of HMB depends on the underlying cause and the patient’s wishes. In some cases, no underlying cause for HMB is found.

Important considerations include the desire for pregnancy (as some management options are contraceptive and others are contraindicated in pregnancy) and co-morbidities.

Patients with underlying structural pathology, suspected malignancy, persistent symptoms despite initial medical management or co-morbidities should be referred to gynaecology.

Medical management

Any medical causes of HMB (e.g. coagulation disorder, hypothyroidism, PCOS) should be identified and treated.

The intrauterine system (IUS) is often used as a first-line treatment for HMB. It is a long-term treatment which can be used for up to 5 years for HMB.

Some patients may experience heavy, irregular bleeding as the IUS thins the endometrial lining. It should ideally be left in situ for at least 12 months to observe the benefit. However, the IUS is unsuitable for women trying to conceive at the time due to its contraceptive effect.

If the IUS is not a suitable option or is declined by the patient, other treatment options can be considered.

Second-line treatments include tranexamic acid, non-steroidal anti-inflammatory drugs (NSAIDs) (e.g. mefenamic acid), or combined hormonal contraception (e.g. the combined pill)

The third-line treatment option for HMB is with progestins (e.g. norethisterone)

Co-existing iron deficiency anaemia should also be treated with iron supplementation. Simple analgesia (paracetamol and NSAIDs) can be a useful adjunct alongside the treatments above to relieve pain during periods.

Surgical management

Patients with an underlying structural cause of HMB may benefit from surgical intervention. Surgical management is also indicated for patients without an underlying structural cause but with persisting symptoms despite medical management.

Surgical management options include:

• Hysteroscopy and endometrial ablation: thermal destruction of the endometrial lining using an instrument inserted through the cervix
• Uterine artery embolisation: often performed by interventional radiologists
• Myomectomy or polypectomy: to remove direct structural causes (fibroids, polyps) of HMB
• Hysterectomy: removal of the uterus to cease uterine bleeding (this is usually a last resort)

The choice of surgical management depends on the underlying aetiology, patient preferences and co-morbidities.

Complications

Complications of HMB include:

• Iron deficiency anaemia
• Psychosocial impact and reduced quality of life
• Complications related to underlying pathology (e.g. PCOS)
• Complications related to medical or surgical intervention

Key points

• Heavy menstrual bleeding (HMB) is excessive menstrual blood loss which interferes with quality of life
• HMB is a symptom and has a variety of structural and non-structural causes
• Patients may present with other symptoms suggestive of underlying pathology (e.g. fibroids, malignancy), or features of iron deficiency anaemia (a common complication)
• The most useful initial investigation is a transvaginal ultrasound scan, a full blood count should also be performed to identify anaemia
• First line medical management is usually with the intrauterine system (Mirena coil) depending on patient wishes and the underlying aetiology
• Complications include iron deficiency anaemia and reduced quality of life 

Reviewers

Ms Helga Consiglio

Consultant Obstetrician

Dr Ashley Jefferies

Community Sexual and Reproductive Health Registrar

Editor

Dr Chris Jefferies

References

• NICE CKS. Menorrhagia (heavy menstrual bleeding). Published in 2023. Available from: [LINK]
• NICE Guideline. Heavy menstrual bleeding: assessment and management. Published in 2018. Available from: [LINK]