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Postmenopausal bleeding is defined as any vaginal bleeding that occurs 12 or more months after your final period. It's never considered a normal finding, which is why every clinical guideline says the same thing: get assessed, promptly. That urgency is warranted. But the outcome isn't always alarming. Studies consistently show that the majority of women investigated for postmenopausal bleeding receive a benign diagnosis. The list below ranks the 7 most common causes from most to least frequent, based on what the research shows in practice.
Why postmenopausal bleeding always needs investigation
The problem with postmenopausal bleeding isn't just what it might indicate. It's that you can't tell from the bleeding itself whether it's serious. The volume doesn't predict the cause. Light spotting can signal endometrial cancer; heavier bleeding can come from a benign polyp. That's why skipping a GP appointment because "it was only a little" is a genuine clinical risk. The standard workup includes a pelvic examination, a transvaginal ultrasound to measure the endometrial thickness, and often a biopsy or hysteroscopy depending on those results.
If you're unsure what to expect from that process, the article on post menopausal bleeding: what it means and what to do covers the investigation pathway in detail. And if you're working out whether a specialist referral is the right next step, finding a menopause specialist who handles gynaecological symptoms is worth considering early.
The 7 most common causes
1. Endometrial atrophy
This is the most common finding. After menopause, falling oestrogen causes the lining of the uterus to thin. That thinned lining becomes fragile and can bleed spontaneously. It sounds alarming but it's a structural, not malignant, change. Treatment is sometimes not needed at all, or involves low-dose local oestrogen.
2. Vaginal atrophy (genitourinary syndrome of menopause)
The vaginal walls also thin after oestrogen withdrawal, becoming dry and easily irritated. Bleeding from vaginal atrophy is often triggered by intercourse, a gynaecological examination, or sometimes nothing obvious at all. Local oestrogen cream or pessaries resolve most cases. It's worth knowing that sex after menopause changes partly because of this tissue thinning, and treatment options exist that most women aren't told about.
3. Endometrial polyps
Polyps are small, benign growths on the uterine lining. They're common in postmenopausal women, particularly those who have used tamoxifen (a breast cancer drug with known uterine effects). Most are removed via hysteroscopy as a day procedure. Recurrence is possible, so follow-up matters.
4. Hormone therapy use
Women using oestrogen-progestogen hormone therapy (MHT or HRT) can experience breakthrough bleeding, particularly in the first 3 to 6 months of treatment or after a dose change. This is a known side effect, not a red flag in itself, but it still needs to be reported to the prescribing clinician so they can rule out other causes and adjust the regimen if needed.
5. Endometrial hyperplasia
Hyperplasia is an overgrowth of the uterine lining, typically caused by oestrogen without adequate progestogen to balance it. It sits on a spectrum: simple hyperplasia without atypia carries a low risk of progression to cancer; atypical hyperplasia carries a substantially higher risk and is often treated with a hysterectomy or progestogen therapy. This is why endometrial thickness on ultrasound matters so much in the initial workup.
6. Cervical causes
Cervical polyps, cervical ectropion, or in rarer cases cervical cancer can produce postmenopausal bleeding. A speculum examination and a current cervical screening test are part of the standard assessment. Cervical cancer is far less common than endometrial causes, but it can't be excluded without looking.
7. Endometrial cancer
This is the diagnosis everyone fears, and for good reason: endometrial cancer is the most common gynaecological cancer in Australia, and postmenopausal bleeding is its most frequent presenting symptom. The reassuring reality is that most postmenopausal bleeding investigations do not return a cancer diagnosis. But when endometrial cancer is caught at stage 1 because a woman sought assessment promptly, the five-year survival rate is above 90 percent. Speed of investigation genuinely changes outcomes here.
Who is at higher risk
Certain factors raise the probability of a more serious cause. Obesity is a significant one: excess adipose tissue produces oestrogen, which stimulates the endometrium over time. Diabetes, hypertension, a personal or family history of endometrial or colorectal cancer, late menopause (after age 55), and never having been pregnant all increase risk. Tamoxifen use is a specific flag for polyps and hyperplasia. None of these mean cancer is certain, but they do mean the investigation needs to be thorough.
What happens at the appointment
Your GP will typically start with a history and a pelvic examination, then refer for a transvaginal ultrasound. An endometrial thickness of 4 mm or less on ultrasound in a postmenopausal woman not on hormone therapy is generally reassuring. Above that threshold, a biopsy is usually recommended. If the ultrasound is inconclusive or the bleeding continues despite a normal result, a hysteroscopy (a camera into the uterus) gives a direct view of the cavity and allows polyp removal at the same time.
Don't wait for a second episode before making an appointment. One episode is enough. The investigation is straightforward, and the peace of mind from a clear result is worth the visit.