Fibroids are benign smooth muscle tumours (leiomyomas) of the myometrium.


  • These are extremely common: around 20-40% of women will be diagnosed (most >40 years old)
    • Much fewer will require treatment
  • Usually are a few cm in diameter but can grow much larger and present as a pelvic mass
  • It is more common in women of afro-caribbean ethnicity

Pathophysiology and Risk

  • Fibroid growth is strongly dependent on oestrogen and progesterone
    • Nulliparity may be a risk factor and pregnancy seems to be a protective factor
    • Fibroid risk/intensity/growth will fall after the menopause
      • Use of HRT can cancel this protective effect
    • In premenopausal women, fibroid growth is cyclical and may cause cyclical symptoms
  • NB Malignant subtypes of fibroids (leiomyosarcoma) are extremely rare
  • Diabetes and hypertension are also risk factors
  • Family history increases risk
  • Fibroids can occur in several locations


  • The majority of fibroids (50%), especially if they are small, are asymptomatic
  • Menorrhagia/Dysmenorrhagia are common (especially in submucosal fibroids
    • Pain may be caused by insufficient blood supply to the fibroids, causing hypoxia and even necrosis of the fibroid tissue
    • This is more common (but not isolated to) pedunculated fibroids, which can rotate on their stalk, causing torsion (this needs to be treated quickly, especially if the fibroid extends into the peritoneal space- as there is a risk of necrosis and rupture to cause a peritonitis)
  • If they grow large enough, a pelvic mass may be felt
    • If this continues to an extent, it may put pressure on the ureters (hydronephrosis; kidney injury; dysuria); on the bladder; on the rectum (constipation); on the sacral plexus (sciatica)
  • They may present as a cause of infertility; or a complicator of pregnancy (pre-term; malpresentation; obstruction; PPH)


  • USS is first-line
    • May show mass with heteregenous texture
  • MRI may show the degree of uterine involvment
  • Laparoscopy/hysteroscopy may be used to biopsy and exclude malignancy
  • Bloods (FBC and hormone screen) may be of some use


  • First line is conservative, or if menorrhagic, treat as appropriate
  • Surgery is the mainstay of treatment (NB GnRH has been suggested by NICE to be used before surgery or if surgery is contra-indicated (6 months only then HRT))
    • hysteroscopic resection
    • hysterectomy if family is complete
    • myomectomy (uterine sparing)
    • uterine artery embolisation (new- high initial success rate but high relapse rate too)

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