Lucan · Conditions

Uterine fibroids

Australian guidance: RANZCOG C-Gyn 27 Fibroids in Infertility + C-Gyn 23 UAE

1. Definition and epidemiology

Uterine fibroids (leiomyomas) are benign monoclonal tumours arising from uterine smooth muscle, typically oestrogen and progesterone dependent in their growth. They are the most common pelvic tumour in women of reproductive age, affecting up to 70% of women by age 50 with clinically significant disease in approximately 25% of cases. In Australia, fibroids are a leading indication for hysterectomy, and Black women globally carry a disproportionate burden of earlier onset and more severe disease compared with women of European ancestry.

2. Pathophysiology

Fibroids arise from a single transformed smooth muscle cell that acquires somatic mutations, most commonly in MED12 (mediator complex subunit 12) or HMGA2 rearrangements. Oestrogen drives growth via oestrogen receptor alpha upregulation and local aromatase activity within the fibroid; progesterone acts as a co-mitogen by stabilising insulin-like growth factor 1 and epidermal growth factor receptor signalling. Fibroids are classified by location relative to the uterine wall: submucosal (SM, protruding into the endometrial cavity), intramural (IM, contained within the myometrium) and subserosal (SS, projecting from the outer uterine surface). Submucosal fibroids distort the endometrial cavity, impair implantation, increase miscarriage risk and cause the heaviest menstrual bleeding. Intramural fibroids may reduce fertility through cavity distortion or altered uterine contractility when large. Subserosal fibroids generally do not impair fertility but may cause pressure symptoms. On macroscopic examination, fibroids are well-circumscribed whorled white-grey masses that compress the surrounding myometrium to form a pseudocapsule; microscopically they show interlacing bundles of bland smooth muscle cells with absent necrosis and rare mitoses, distinguishing them from leiomyosarcoma (Robbins Ch 22).

3. Clinical presentation and diagnostic criteria

Most fibroids are asymptomatic and discovered incidentally on pelvic ultrasound. When symptomatic, the dominant features relate to fibroid position and size. Submucosal fibroids classically cause heavy menstrual bleeding (HMB) with passage of clots and secondary iron deficiency anaemia. Intramural and subserosal fibroids more commonly produce bulk symptoms including pelvic pressure, urinary frequency from bladder compression, constipation, and dysmenorrhoea. Infertility or recurrent miscarriage may be the presenting complaint, particularly with submucosal or large intramural disease. On examination, the uterus is typically enlarged, irregular and non-tender with a firm consistency; a fibroid uterus can reach the umbilicus in advanced cases. Acute degeneration (most common in pregnancy) presents with sudden focal pain and low-grade fever.

4. Investigations and AU-specific cutoffs

The investigation pathway follows a stepwise approach anchored to clinical indication.

First line: transvaginal ultrasound (TVUS) is the standard initial imaging modality and adequately characterises most fibroids by size, number and gross location.

Second line for fertility evaluation: RANZCOG C-Gyn 27 states that TVUS and hysterosalpingography (HSG) are insufficiently sensitive or specific for excluding cavity involvement. The preferred modalities to define submucosal extension are MRI, sonohysterography or hysteroscopy. Hysteroscopic assessment may under-represent submucosal lesions due to raised intrauterine pressure causing temporary regression of the fibroid contour, so MRI or sonohysterography is preferred when cavity involvement is uncertain.

Additional investigations: full blood count to detect iron deficiency anaemia from HMB; serum ferritin if anaemia is suspected; endometrial biopsy if there is abnormal uterine bleeding or age over 40 to exclude endometrial pathology; renal tract ultrasound if ureteric obstruction is suspected from a large fibroid mass.

There are no AU-specific haemoglobin or ferritin cutoffs unique to fibroids; standard haematology reference intervals apply, with haemoglobin below 120 g/L in women indicating anaemia warranting correction before elective surgery.

5. Management

Management is guided by symptom burden, fibroid size and location, desire for fertility preservation and proximity to menopause.

Expectant management is appropriate for asymptomatic fibroids regardless of size, with reassurance and annual review.

Surgical management is first line for symptomatic disease or fertility-impairing fibroids. Myomectomy is the accepted fertility-preserving surgical option and may be performed via hysteroscopy (submucosal fibroids), laparoscopy or laparotomy depending on fibroid size and location. RANZCOG C-Gyn 27 identifies the following as indications for myomectomy in women with infertility: demonstration of submucosal fibroids; symptomatic fibroids causing HMB or pressure symptoms even when fertility benefit is uncertain; and multiple failed Assisted Reproductive Technology (ART) cycles where the female partner has intramural fibroids. Hysteroscopic myomectomy for SM fibroids is likely to improve fertility outcomes, though evidence quality is limited. Evidence is insufficient to confirm that myomectomy for IM fibroids improves fertility outcomes when the cavity is not distorted.

Uterine artery embolisation (UAE) is a minimally invasive radiological option for women with symptomatic fibroids who wish to preserve the uterus but do not require future fertility. Per RANZCOG C-Gyn 23, UAE achieves durable reduction in fibroid volume and symptomatic control in the majority of treated women. UAE is not recommended for women wishing to conceive, and it is contraindicated in the setting of active pelvic infection, unexplained uterine or cervical malignancy, and severe contrast allergy.

Hysterectomy is definitive treatment and is appropriate for women who have completed childbearing with severe symptoms unresponsive to conservative measures.

6. Pharmacology and AU PBS notes

Medical treatment does not cure fibroids but may manage symptoms or reduce fibroid volume pre-operatively.

Progestogen-releasing intrauterine device (levonorgestrel intrauterine system, Mirena): reduces HMB associated with intramural fibroids without cavity distortion; not PBS restricted for this indication but listed for heavy menstrual bleeding under PBS item 4147H.

Combined oral contraceptive pill: reduces HMB through endometrial atrophy; no PBS restriction.

GnRH analogues (leuprorelin acetate, Lucrin; nafarelin, Synarel): induce a hypo-oestrogenic state that shrinks fibroid volume by 30 to 50% over 3 months. Used short term (up to 6 months) for pre-operative correction of anaemia or fibroid volume reduction before myomectomy. Prolonged use causes bone mineral density loss. RANZCOG C-Gyn 27 notes that short-term GnRH analogue use is appropriate for pre-operative optimisation in infertile women. PBS restricted for endometriosis; fibroid use is typically off-label or via private prescription.

Ulipristal acetate (Esmya): previously used for pre-operative fibroid reduction, but RANZCOG C-Gyn 27 explicitly states it is not recommended in infertile women due to significant adverse effects including serious liver injury. The European Medicines Agency placed it under review in 2018 and it is not in routine Australian clinical use.

Tranexamic acid: reduces HMB by inhibiting fibrinolysis; taken during menstruation only; available without prescription (Cyklokapron).

NSAIDs (mefenamic acid, ibuprofen): reduce menstrual blood loss and dysmenorrhoea; second-line adjunct.

7. Complications and monitoring

Surgical complications of myomectomy include intraoperative haemorrhage (risk increases with multiple or large fibroids), uterine wall defect requiring repair, inadvertent bowel or bladder injury, adhesion formation and, rarely, conversion to hysterectomy. Uterine rupture in a subsequent pregnancy is a recognised risk after deep intramural myomectomy; caesarean delivery is typically recommended depending on the depth of myometrial entry at the time of surgery.

UAE complications include post-embolisation syndrome (fever, pain, nausea in the first 48 to 72 hours), non-target embolisation, ovarian failure in up to 3% of women (higher risk over age 45), fibroid expulsion, and rare uterine necrosis requiring hysterectomy. Women considering UAE who have not completed childbearing should be counselled about the uncertain reproductive implications.

Fibroid surveillance for asymptomatic disease: annual TVUS is reasonable for monitoring growth trajectory; rapid increase in size warrants MRI to exclude leiomyosarcoma, though malignant change is rare (estimated at less than 0.5%). Women approaching menopause with asymptomatic fibroids can be reassured that oestrogen withdrawal after menopause typically leads to fibroid regression.

Iron deficiency anaemia from HMB should be corrected with oral ferrous sulphate (Ferro-Gradumet) before elective surgery; intravenous iron (Ferinject) is used when oral iron is not tolerated or when pre-operative time is short.

Written for Australian practice and grounded in the guidance named above. Study material only — not medical advice. Always check against current guidelines.