Heavy Menstrual Bleeding & Abnormal Uterine Bleeding

The unified approach to abnormal uterine bleeding (AUB) — its classification, red flags and work-up — and the detailed management of heavy menstrual bleeding (HMB), the commonest pattern. Two specific bleeding presentations keep their own pages: Intermenstrual & post-coital bleeding and Post-menopausal bleeding. Structural causes are cross-referenced to Uterine fibroids, Adenomyosis and Endometrial cancer.

Normal vs abnormal

• Normal cycle: length 24–38 days, bleeding 2–9 days, up to ~1 pad/tampon every 3 h.
• Benign/normal variants: ovulation spotting (~mid-cycle), a few days’ spotting around the period, irregular cycles in teenagers and perimenopause, an occasional one-off missed/early period (exclude pregnancy). Breakthrough bleeding is expected in the first ~3 months on a COC and first ~6 months on implant/LNG-IUD/DMPA.
• HMB is >80 mL loss per cycle, or bleeding >7 days — but practically, any bleeding the woman finds unacceptable counts and warrants assessment.

PALM-COEIN classification (FIGO)

Structural (imaging/histology) vs non-structural causes of AUB:

Structural — PALM	Non-structural — COEIN
Polyp (endometrial, endocervical)	Coagulopathy (von Willebrand disease, platelet dysfunction/thrombocytopenia)
Adenomyosis	Ovulatory dysfunction (anovulatory/disturbed cycles, PCOS, thyroid disease)
Leiomyoma (fibroids)	Endometrial (endometritis, local molecular haemostatic disturbance)
Malignancy & hyperplasia	Iatrogenic (hormonal contraception, anticoagulants, copper IUD)
	Not yet classified (undiagnosed pregnancy complication, trauma, foreign body)

HMB is more commonly associated with ovulatory (regular) cycles; when no pathology is found it is attributed to local endometrial haemostatic dysfunction. Anovulatory (irregular) bleeding always needs a hormonal treatment component.

Serious causes not to miss

• Pregnancy / ectopic — always exclude with a pregnancy test.
• Infection — chlamydia (often causes IMB/PCB with pain and discharge).
• Endometrial carcinoma / hyperplasia — heavy, erratic, frequent or intermenstrual bleeding. Risk factors: age >40, obesity (>90 kg), unopposed oestrogen, nulliparity (2–3×), PCOS (2–3×), exogenous unopposed oestrogen (~9×), tamoxifen, family history (endometrial/breast/bowel) — remember “over 40, overweight, over-oestrogenised, family history.” Rare under 40. See Endometrial cancer.
• Cervical carcinoma — post-coital or intermenstrual bleeding. A normal cervical screen does not exclude it (10–15% false-negative in the presence of bleeding).

Postcoital, persistent intermenstrual, persistent postmenopausal bleeding, or unexplained persistent unusual discharge all require a clinician-collected co-test (HPV + LBC) — a self-collected (HPV-only) sample is not appropriate — and referral for specialist investigation to exclude genital-tract malignancy regardless of the co-test result. See Cervical screening.

Assessment

History: age, parity, LMP and pregnancy likelihood; cycle frequency/volume/pattern (regular vs irregular); impact on quality of life; anaemia symptoms; pain or pressure; comorbidities (thyroid, PCOS, obesity, bleeding disorders); medications (anticoagulants, tamoxifen, steroids, SSRIs, tricyclics, antipsychotics, copper IUD); STI and cervical screening history; family history (endometriosis, endometrial/bowel cancer). A recent change in pattern, or associated pain, points to structural pathology; surface lesions (polyp, cervical pathology) typically cause IMB/PCB.

Examination: haemodynamic stability, BMI, pallor/anaemia, androgen excess, bruising/ petechiae, thyroid, abdominal masses; speculum + bimanual (uterine size, tenderness, adnexal masses).

Investigations:

• Pregnancy test and FBC are the essentials.
• Ferritin ± TSH; coagulation studies only if personal/family bleeding history.
• Endocervical PCR for chlamydia/gonorrhoea if history suggests; cervical screening if due (a normal screen doesn’t exclude endometrial cancer).
• Sex-hormone testing (oestradiol/FSH/LH) is NOT required for regular ovulatory bleeders.
• Pelvic ultrasound (transvaginal preferred, ideally days 4–7) when there is suspected uterine pathology or failure of a medical trial — for regular cycles, over 40 or younger with no response; for irregular cycles, all reproductive-age or perimenopausal women, or a pelvic mass. Hysteroscopy if USS is inconclusive or shows pathology; endometrial biopsy to exclude hyperplasia.

Endometrial-thickness thresholds (Cancer Australia framework): in a low-risk woman with a first episode and no anaemia, treat the bleeding and exit if it settles. If risk factors, anaemia, or persistence: TVUSS in the first half of the cycle — biopsy/refer if endometrium >12 mm (premenopausal) or >5 mm (perimenopausal), or if bleeding persists despite treatment. (For postmenopausal bleeding, the threshold is >4 mm — see that page.)

Managing heavy menstrual bleeding

When no structural pathology is found, choice depends on age, parity, comorbidities, contraceptive need and preference. Anovulatory cycles must include hormonal treatment; otherwise ovulatory and anovulatory HMB are managed the same way.

Ranked options (eTG):

1. 52 mg LNG-IUD — the most effective medical therapy and first-line even when contraception isn’t otherwise wanted. (The 19.5 mg Kyleena is not indicated for HMB.) Replace every 5 years for the HMB indication.
2. Tranexamic acid — 1–1.5 g orally 6–8-hourly for the first 3–5 days of menses; antifibrinolytic, reduces loss; more effective than NSAIDs for blood loss.
3. NSAIDs — as for dysmenorrhoea; help concurrent period pain.
4. Combined hormonal contraception (COC/ring) — second-line, equivalent to TXA/NSAIDs; use extended/continuous dosing. Estradiol valerate + dienogest (Qlaira) carries a specific TGA indication for heavy/prolonged bleeding.
5. Oral progestogens — the POP is not recommended for HMB. Cyclical oral progestogens are a short-term option (≤6 months; hypo-oestrogenism risk) when others are unsuitable:

Ovulatory cycles (days 1–21 of a 28-day cycle, up to 6 months)
medroxyprogesterone 10 mg orally, 1–3 times daily (by bleeding heaviness), OR
norethisterone 5 mg orally, 2–3 times daily

Anovulatory cycles (same 12 days of each calendar month)
medroxyprogesterone 10 mg orally once daily, OR norethisterone 5 mg orally once daily

Surgical treatment (endometrial ablation or hysterectomy) — for women who no longer wish to conceive, are perimenopausal, have poorly controlled symptoms, drug adverse effects, or significant uterine pathology. Endometrial hyperplasia with atypia → hysterectomy (ablation is not appropriate).

Acute emergency HMB

Unstable observations → ED. Otherwise:

tranexamic acid 10 mg/kg IV every 8 h until bleeding stops, OR 1–1.5 g orally 6–8-hourly until it stops

If TXA is unavailable/not tolerated, hormonal options: a 30–35 microgram ethinyloestradiol COC 6-hourly (re-evaluate at 48 h), or medroxyprogesterone 10 mg 4-hourly (max 80 mg/day), or norethisterone 5–10 mg 4-hourly, until bleeding stops.

Referral

• Haemodynamic compromise → phone 000 / emergency assessment.
• Stable but Hb <80 g/L → acute gynaecology referral.
• Features suspicious of malignancy (persistent PCB >4 weeks in age >35; unexplained vulval lump/ulcer/bleeding; palpable vaginal mass; ascites or a non-fibroid pelvic mass; cervix looking like cancer) → gynaecological-cancer referral.
• Abnormal ultrasound (endometrium >12 mm, fibroids, polyps) or failed medical treatment → non-acute gynaecology referral.

Endometrial polyps (brief)

Localised endometrial outgrowths; cause IMB/HMB/PMB (rarely PCB). Usually benign, rarely malignant; may reduce fertility. Small asymptomatic polyps often resolve — watchful waiting; if bleeding or subfertility, hysteroscopic polypectomy (preferred over blind D&C, which risks missing/incompletely removing the polyp).