Uterine Fibroids

Overview – Uterine Fibroids

Uterine fibroids, also known as leiomyomas or fibromyomas, are benign smooth muscle tumours of the uterus. They are common in women of reproductive and perimenopausal age, often presenting with heavy menstrual bleeding (menorrhagia), pelvic pressure symptoms, or infertility. Their growth is oestrogen-dependent, making them highly responsive to hormonal fluctuations such as pregnancy and menopause.

Definition

Uterine fibroids are benign tumours of the uterine smooth muscle (myometrium). They may be solitary or, more commonly, multiple nodules of variable size and location.

Aetiology

  • Likely multifactorial, but with a key dependence on oestrogen
    • Explains:
      • Growth acceleration during pregnancy
      • Regression post-menopause

Pathogenesis

  • Hyperplasia or tumourigenesis of myometrial smooth muscle cells
  • Subsequent enlargement driven by oestrogen stimulation
  • No malignant potential, but size and location can significantly impact clinical presentation
UTERINE FIBROIDS
https://www.healthdirect.gov.au/uterine-fibroids

Morphology

Macroscopic

  • Round, well-circumscribed, white/tan solid nodules
  • Range in size from microscopic to massive (e.g. grapefruit-sized)
  • Typically multiple fibroids present

Microscopic

  • Whorled bundles of uniform spindle-shaped smooth muscle cells
  • Cigar-shaped nuclei
  • Well-demarcated margins (though not encapsulated)
UTERINE FIBROID
Hic et nunc, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons

Clinical Features

Epidemiology

  • Affects <30% of women, often undiagnosed if asymptomatic
  • Most common in perimenopausal women

Symptoms

  • Asymptomatic if small
  • Menorrhagia (long, heavy periods lasting 8–14 days)
  • Dyspareunia (pain during intercourse)
  • Pelvic pressure symptoms:
    • Bloating
    • Heaviness
    • Abdominal mass
    • Constipation
    • Urinary frequency/urgency due to compression on bladder

Investigations

  • Transvaginal ultrasound – First-line imaging
  • Bimanual pelvic examination – May detect large fibroids
  • Consider MRI or hysteroscopy in complex cases

Management

Medical

  • Hormonal suppression (e.g. progesterone agents, GnRH analogues) – May reduce size or control symptoms
  • Iron supplementation if anaemia from blood loss

Surgical

  • Myomectomy – For women desiring fertility
  • Hysterectomy – Definitive treatment for symptomatic or large fibroids
  • Uterine artery embolisation – Alternative minimally invasive approach

Complications

  • Infertility and miscarriage – Due to distortion of uterine cavity
  • Heavy bleeding – Leading to iron-deficiency anaemia
  • Post-renal failure – From ureteric compression and obstruction

Differential Diagnosis

Summary – Uterine Fibroids

Uterine fibroids are benign, oestrogen-dependent smooth muscle tumours that commonly cause menorrhagia, pelvic discomfort, and fertility issues. They are a leading cause of gynaecological surgery and must be considered in any patient presenting with abnormal uterine bleeding. For a broader context, see our Reproductive Health Overview page.

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