What Is the Most Common Reason for Bleeding After Menopause?

Seeing a spot of blood after you have officially reached menopause can be incredibly frightening. As a Menopause Specialist, I hear the panic in my patients’ voices when this happens. You’ve gone 12 months without a period, closed that chapter, and suddenly—there is bleeding.

First, take a deep breath. While postmenopausal bleeding (PMB) is a “red flag” symptom that must always be investigated, the vast majority of cases are not caused by cancer. In fact, roughly 90% of women referred for postmenopausal bleeding do not have a malignancy.

This article outlines exactly what causes these bleeds, with a focus on the most common reasons, and explains the specific pathway we use in the UK to ensure you are safe.

What Counts as Postmenopausal Bleeding?

Menopause is defined retrospectively as 12 consecutive months without a menstrual period. Postmenopausal bleeding is any vaginal bleeding—no matter how light, pink, or brown—that occurs after this 12-month mark.

It does not matter if it is:

• A single spot of pink on the tissue.
• Brown, old-looking discharge.
• Heavier, fresh red bleeding.

According to NICE and BMS guidance, even a “one-off” bleed requires urgent evaluation. If you are still having irregular cycles, you may find our guide on Perimenopause Bleeding Between Periods helpful, as the management differs slightly before the 12-month mark.

The Most Common Reason: Genitourinary Syndrome of Menopause (GSM)

To answer the main question: What is the most common reason for bleeding after menopause?

Statistically, the most frequent benign cause is Atrophy (thinning of the tissues). This is now often referred to under the umbrella term Genitourinary Syndrome of Menopause (GSM).

When your estrogen levels drop permanently after menopause, the tissues lining the vagina and the uterus (endometrium) become thinner, drier, and more fragile. This condition, known as endometrial atrophy or vaginal atrophy, makes the blood vessels just below the surface prone to breaking.

• Vaginal Atrophy: Friction from walking, exercise, or intercourse can cause these fragile tissues to tear slightly and bleed.
• Endometrial Atrophy: The lining of the womb becomes so thin that it becomes unstable and sheds, causing spotting.

While this is the most common benign finding, we can never assume it is atrophy until we have ruled out serious pathology.

Other Common Causes of Abnormal Bleeding After Menopause

While atrophy is common, several other factors can trigger vaginal bleeding after menopause:

1. Cervical or Endometrial Polyps

Polyps are fleshy growths that develop in the lining of the womb (endometrium) or the neck of the womb (cervical). They are usually benign (non-cancerous), but they are highly vascular and prone to bleeding. 

2. Endometrial Hyperplasia

This is the opposite of atrophy. Here, the lining of the womb becomes too thick. This can happen if there is excess estrogen (perhaps from body fat or unbalanced HRT). Hyperplasia is a risk factor because, in some cases, it can develop into atypical cells or cancer if left untreated.

3. HRT-Related Bleeding

If you are on Menopause Treatment for Symptom Relief (HRT), bleeding can sometimes occur.

• Sequential HRT: Monthly withdrawal bleeds are expected.
• Continuous HRT: If you are on a “bleed-free” regime but experience spotting, it requires a check-up, especially if it starts occurring months or years after you were stable.
• Compliance: Missing a dose or issues with patch adhesion can trigger a bleed.

4. Endometrial Cancer

This is the diagnosis we are testing to rule out. Approximately 10% of women with postmenopausal bleeding may have uterine cancer. However, the good news is that because bleeding happens early in the disease process, it is often caught at a highly curable stage. This is why we never ignore the symptom.

Investigations: What to Expect

If you present with bleeding after menopause reasons, guidelines dictate a rapid referral (often called the “2-week wait” pathway in the NHS). Here is what we do:

• Clinical History & Exam: We check your cervix to rule out visible issues like ectropion or cervical polyps.
• Transvaginal Ultrasound (TVS): This is the gold standard first-line test. We measure the “endometrial thickness” (ET).
  • If the lining is thin (usually <4mm), the risk of cancer is extremely low (less than 1%), and further invasive tests may not be needed.
  • If the lining is thickened (≥4mm) or fluid is present, we proceed to the next step.
• Hysteroscopy & Biopsy: A tiny camera is passed into the womb to visualise the cavity. We can take a biopsy (sample) of the lining or remove polyps there and then. This is the definitive way to diagnose menopause bleeding causes and treatment needs.

Management and Treatment

Once the cause is found, treatment is usually straightforward:

• For Atrophy: We treat the underlying dryness. Local vaginal estrogen (creams, pessaries, or rings) is highly effective at plumping up the tissues and stopping the bleeding.
• For Polyps: These are usually removed during hysteroscopy. It is a quick procedure, and once removed, the bleeding usually stops permanently.
• For Hyperplasia: This is often treated with progesterone (such as the Mirena coil or oral tablets) to thin the lining back down.
• For HRT issues: We may adjust your dose or change the type of progesterone you are taking.

Summary

While abnormal bleeding after menopause should always be treated as a priority alert, the outcome is frequently reassuring.

• Never ignore it: Any bleed after 12 months of amenorrhea needs a doctor’s check.
• Most causes are benign: Endometrial atrophy bleeding and polyps are leading causes.
• The pathway is fast: Guidelines ensure you are seen and scanned quickly to rule out sinister causes.
• Treatment works: Whether it’s removing a polyp or treating dryness, we can resolve the issue.