Leiomyoma (Uterine Fibroids)

Definition | Aetiology | Types of Fibroids | Risk Factors | Clinical Presentation | Investigations | Management | When to Refer | References

Definition

Leiomyomas, commonly known as uterine fibroids, are benign smooth muscle tumours of the uterus. They are the most common pelvic tumours in women and can vary in size, number, and location within the uterus. While often asymptomatic, they can cause significant morbidity in some women.

Aetiology

The exact cause of leiomyomas is not fully understood, but several factors are thought to contribute to their development:

• Hormonal Influence: Oestrogen and progesterone promote the growth of fibroids, which typically shrink after menopause.
• Genetic Predisposition: A family history of fibroids increases the likelihood of developing them.
• Growth Factors: Growth factors like insulin-like growth factor (IGF) may also play a role in the development and growth of fibroids.

Types of Fibroids

Fibroids are classified based on their location within the uterus:

• Intramural Fibroids: Located within the muscular wall of the uterus. These are the most common type and can cause a range of symptoms depending on their size and location.
• Subserosal Fibroids: Grow on the outer surface of the uterus, extending into the pelvic cavity. They can cause pressure symptoms on adjacent organs but are less likely to affect menstruation.
• Submucosal Fibroids: Develop just under the lining of the uterine cavity. These can cause heavy menstrual bleeding and are often associated with infertility and miscarriage.
• Pedunculated Fibroids: Attached to the uterus by a stalk, they can be either subserosal or submucosal. Torsion of a pedunculated fibroid can cause acute pain.

Risk Factors

Several factors increase the likelihood of developing leiomyomas:

• Age: Fibroids are more common in women of reproductive age, particularly in their 30s and 40s.
• Family History: A family history of fibroids increases the risk.
• Ethnicity: Fibroids are more common and tend to be more severe in Black women compared to women of other ethnicities.
• Obesity: Higher body mass index (BMI) is associated with an increased risk of fibroids.
• Early Menarche: Starting menstruation at an early age is linked to a higher risk of developing fibroids.
• Nulliparity: Women who have never given birth are at higher risk.

Clinical Presentation

Many women with leiomyomas are asymptomatic, but when symptoms do occur, they can include:

• Menorrhagia: Heavy and prolonged menstrual bleeding, often leading to anaemia.
• Dysmenorrhoea: Painful periods, often due to increased uterine contractility.
• Pelvic Pressure or Pain: A feeling of fullness or pressure in the pelvis, sometimes accompanied by lower back pain.
• Urinary Symptoms: Frequency or urgency, particularly if fibroids press on the bladder.
• Bowel Symptoms: Constipation or bloating, particularly if fibroids press on the rectum.
• Dyspareunia: Pain during sexual intercourse, depending on the location of the fibroids.
• Reproductive Issues: Infertility, recurrent miscarriage, or complications during pregnancy, such as preterm labour.

Investigations

The diagnosis of leiomyomas may involve a combination of clinical assessment and imaging:

• Pelvic Examination: A bimanual examination may reveal an enlarged, irregularly shaped uterus suggestive of fibroids.
• Ultrasound: Transvaginal ultrasound is the first-line imaging modality for diagnosing fibroids, allowing assessment of size, location, and number of fibroids.
• MRI Scan: Used in complex cases to provide detailed imaging, particularly when planning surgery or assessing the relationship of fibroids to adjacent structures.
• Hysteroscopy: A procedure to inspect the uterine cavity, particularly useful for diagnosing and potentially treating submucosal fibroids.
• Full Blood Count (FBC): To assess for anaemia in women with heavy menstrual bleeding.

Management

The management of leiomyomas depends on the severity of symptoms, the size and location of fibroids, and the woman's desire for fertility preservation:

Conservative Management

• Watchful Waiting: In asymptomatic women or those with mild symptoms, regular monitoring without active treatment may be appropriate, especially as fibroids often shrink after menopause.
• Pharmacological Management:
  • Non-Steroidal Anti-Inflammatory Drugs (NSAIDs): For managing pain and reducing menstrual blood loss.
  • Tranexamic Acid: An antifibrinolytic used during menstruation to reduce heavy bleeding.
  • Hormonal Therapy:
    • Combined Oral Contraceptive Pill (COCP): Can help regulate menstrual cycles and reduce bleeding.
    • Progesterone-only therapies: Such as norethisterone or the levonorgestrel-releasing intrauterine system (LNG-IUS), which can reduce menstrual blood loss and provide contraception.
    • GnRH Agonists: Used short-term to shrink fibroids pre-operatively or to manage symptoms in women nearing menopause.

Surgical Management

• Myomectomy: Surgical removal of fibroids, preserving the uterus. It is an option for women who wish to maintain fertility.
• Hysterectomy: The definitive treatment for fibroids, involving the removal of the uterus. This is typically considered in women with severe symptoms who do not desire future fertility.
• Uterine Artery Embolisation (UAE): A minimally invasive procedure that cuts off the blood supply to fibroids, causing them to shrink.
• Endometrial Ablation: A procedure to remove the lining of the uterus, reducing menstrual bleeding, particularly effective for submucosal fibroids.
• Magnetic Resonance-guided Focused Ultrasound Surgery (MRgFUS): A non-invasive treatment option that uses focused ultrasound waves to destroy fibroid tissue.

When to Refer

Referral to a gynaecologist is warranted in the following situations:

• Severe symptoms such as heavy menstrual bleeding, pain, or pressure symptoms that do not respond to medical treatment.
• Rapidly growing fibroids, or those suspected to be causing significant reproductive issues.
• Uncertainty in diagnosis or if malignancy (e.g., leiomyosarcoma) is suspected.
• Consideration of surgical treatment, particularly in women who wish to preserve fertility.

References

1. NHS (2024) Uterine Fibroids. Available at: https://www.nhs.uk/conditions/fibroids/ (Accessed: 26 August 2024).
2. National Institute for Health and Care Excellence (2024) Uterine Fibroids: Diagnosis and Management. Available at: https://www.nice.org.uk/guidance/ng88 (Accessed: 26 August 2024).
3. British Medical Journal (2024) Management of Uterine Fibroids. Available at: https://www.bmj.com/content/350/bmj.g980 (Accessed: 26 August 2024).

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