Synopsis
Treat postmenopausal bleeding as a cancer-exclusion presentation, localise genital and non-genital sources, interpret transvaginal endometrial thresholds in ordinary and HRT contexts, and escalate persistent or recurrent bleeding to histology.
- Postmenopausal bleeding means vaginal bleeding after at least 12 months of spontaneous amenorrhoea from menopause; ask about HRT, tamoxifen, anticoagulants and whether blood may be urinary or rectal.
- Refer unexplained PMB through the urgent suspected-cancer pathway at age 55 or older under NICE and consider the same pathway in younger patients.
- Examine vulva, vagina and cervix with consent and a chaperone to identify atrophy, trauma, polyp or visible malignancy, but continue endometrial assessment even when atrophy seems likely.
- Transvaginal ultrasound is the usual initial endometrial triage test; report whether the whole double-layer endometrium is seen, its maximum thickness, uniformity and any focal lesion or fluid.
- A fully visualised uniform endometrium of 4 mm or less commonly defines low endometrial-cancer probability in non-HRT PMB pathways, but recurrence still requires further assessment.
- An endometrium above 4 mm, irregular, focally abnormal or inadequately visualised generally leads to endometrial sampling and often hysteroscopy under the local urgent pathway.
- For unscheduled bleeding on HRT, British Menopause Society guidance uses reassuring thresholds of 4 mm or less on continuous combined HRT and 7 mm or less on sequential HRT when the lining is uniform and fully seen.
- BMS advises urgent transvaginal ultrasound when bleeding first presents more than six months after starting HRT or more than three months after changing it, or sooner for heavy bleeding or risk factors.
- Pipelle sampling can detect global endometrial disease but may miss a focal polyp; persistent symptoms, focal ultrasound findings or insufficient tissue requires hysteroscopy-directed assessment.
- Treat vaginal atrophy or adjust HRT only after appropriate cancer exclusion, and give explicit instructions to return for any recurrent blood, spotting or discharge.
Key red flags
Any genital bleeding more than 12 months after the final spontaneous menstrual period is abnormal and should not be dismissed as a late period.
NICE recommends suspected-cancer referral for unexplained postmenopausal bleeding at age 55 or older and consideration of that pathway below 55.
A pelvic mass, offensive or blood-stained discharge, weight loss, anaemia, suspicious cervix or vulval lesion increases urgency and may indicate disease outside the endometrium.
Persistent or recurrent bleeding requires renewed cavity assessment even after a fully visualised thin endometrium or benign initial biopsy.
Tamoxifen can produce polyps and cystic endometrial change; ultrasound thickness is less reliable and symptomatic patients often need direct cavity assessment.
An endometrium that is irregular, focally abnormal or not completely visualised cannot be called reassuring by using the measurable thin segment.
A second episode after an initially reassuring scan can reflect a missed focal lesion and reactivates specialist assessment.
Investigation priorities
Apply NICE age and symptom criteria and avoid delay while routine tests are arranged.
Management branches
Any unexplained genital bleeding occurs after established menopause.
- Apply NICE suspected-cancer referral criteria immediately, document HRT, tamoxifen, anticoagulants, risk and whether urinary or rectal bleeding is possible.
- Perform consented vulval, speculum and pelvic examination and arrange transvaginal ultrasound within the urgent local pathway.
- Use thickness, uniformity, focal findings and visualisation quality to determine biopsy, hysteroscopy or carefully safety-netted discharge.