Bleeding decoder: what your bleeding pattern can mean

"Heavier periods" in a 46-year-old whose cycles have gone erratic is usually the ordinary physiology of perimenopause. A single streak of brown two years after your last period is postmenopausal bleeding, and it is investigated every time. Same symptom on paper; completely different situations. So this tool asks where you are first — and only then asks what the bleeding is doing. It will not tell you what is causing your bleeding, and it will never tell you to start, stop or change a medicine or an HRT dose.

This explains what a bleeding pattern can mean at your stage. It is NOT a diagnosis. It cannot tell you what is causing your bleeding, and it will never tell you to start, stop or change a medicine or an HRT dose — that is a conversation with the person who prescribes it. Only a clinician who can examine you can say what your bleeding actually means.

1. Where are you? Start here — the same bleeding means different things at different stages.

My periods are still regularCycles arrive roughly when you expect them.Perimenopause — my periods have become irregularCycles are shifting: closer together, further apart, heavier, lighter, skipped.Postmenopause — no period for 12+ monthsYour last period was more than a year ago.On sequential (cyclical) HRTYou take progestogen for part of each month — usually still having periods or recently stopped.On continuous combined HRTYou take estrogen and progestogen every day, on a no-bleed regimen.

Pick your stage to go on. This is not a formality. Heavier periods in perimenopause and a streak of blood two years after your last period are the same symptom on paper and completely different situations in practice — one is usually ordinary, the other is always investigated. The tool cannot say anything useful until it knows which you are.

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What the workup usually looks like

An examination. A look at the vulva, vagina and cervix — often the fastest way to find atrophy, a polyp, or a cervical cause. Your cervical screening history gets checked too.
A transvaginal ultrasound, which measures the thickness of your endometrium (the lining of the womb). In postmenopausal women who are not on HRT, a threshold of around 4 mm is commonly used: a lining at or below it makes cancer unlikely and a biopsy may not be needed straight away, while a thicker lining leads to sampling. The threshold does not transfer to women on HRT, and it is not a rule that holds for everyone.
An endometrial biopsy — a thin tube passed through the cervix to take a sample of the lining, usually in clinic, usually a few crampy minutes.
Hysteroscopy if more is needed — a thin camera that actually looks inside the womb, which can find a polyp or a focal patch that an ultrasound measurement misses entirely.

The caveat that matters most: a thin lining does not close the question if the bleeding continues. An endometrial thickness under the threshold makes cancer unlikely; it does not make it impossible, and it says nothing about a polyp or a focal lesion sitting in one spot. If you bleed again after a reassuring scan, that is new information — go back and say so. A normal result is a snapshot of that day, not a permanent answer, and persistent bleeding is investigated further regardless of what the scan showed.

Get urgent care today — do not wait for a routine appointment

Flooding — soaking through a pad or tampon every hour for two hours or more
Passing large clots with dizziness, breathlessness, a racing heart, or fainting
Feeling faint, very pale, or short of breath on light activity while bleeding
Severe pelvic or abdominal pain
Fever, chills, or foul-smelling discharge with bleeding
Any bleeding at all if you are or could be pregnant
Any bleeding after 12+ months with no period — this does not need an emergency department, but it does need an appointment booked now rather than watched

Explanations drawn from ACOG, the NHS, NICE, Cancer Research UK, the National Cancer Institute (NIH) and MedlinePlus (NIH). This tool never diagnoses and never recommends a treatment. It will not tell you to start, stop, or change a medication or an HRT dose — including the progestogen part, which is what protects the womb lining. Take the pattern to a clinician, and take your HRT prescriber the question of what to do about it.

Why the stage changes the answer

Almost every guide to abnormal bleeding lists symptoms and their causes as if the two connected directly. They do not. The information that decides what a bleeding pattern means is not the bleeding — it is where you are standing when it happens.

In perimenopause, ovulation becomes unreliable. Without ovulation there is no corpus luteum, without a corpus luteum there is little progesterone, and without progesterone the womb lining keeps building under estrogen with nothing to shed it on schedule. That is the engine behind almost everything women report in these years: cycles that come close together and then vanish for months, periods that are far heavier than they used to be, bleeds that drag on, spotting in between. It is common, it is expected, and most of the time it is exactly what it looks like.

After menopause, that engine has stopped. Estrogen is low, the lining is thin and quiet, and there is no mechanism that produces a bleed. So when blood appears anyway, something is producing it — and that something has to be identified. This is the whole reason postmenopausal bleeding has a rule attached that almost nothing else in women's health does.

Postmenopausal bleeding: the line that never moves

Once you have gone 12 months with no period, any bleeding is postmenopausal bleeding. Any amount. Any colour. Once, or repeatedly. Already stopped, or still going. A full bleed, a smear on the paper, brown discharge you nearly did not notice. There is no minimum that makes it count, and there is no version that is watched instead of investigated.

The numbers behind that rule are worth knowing, because they explain it rather than just assert it. Around 90% of postmenopausal bleeding turns out to be benign — most often atrophy, where thin and fragile tissue in the vagina or the womb lining bleeds easily. That is genuinely reassuring, and it is the likeliest outcome. But roughly 1 in 10 women with postmenopausal bleeding has endometrial cancer. Endometrial cancer found early is highly curable. Found late, it is a much harder disease.

Put those three facts together and the logic writes itself: the odds are good, the treatable window is real, and the cost of waiting is the one thing you cannot get back. That is why this is the symptom not to sleep on — not because it is usually cancer, but because it is the rare case where a few weeks of "let's see if it happens again" can change the outcome.

Two traps in particular catch women here. The first is brown discharge only — it does not look like blood, so it does not feel like bleeding. It is old blood, and it counts. The second is bleeding with an obvious trigger, most often after sex: because you can point at a cause, it feels explained. Vaginal atrophy really is the most likely answer — and a plausible mechanism is still not an investigation. The lining of the womb has to be looked at anyway.

Perimenopause: common, and still not "just perimenopause"

The mirror-image error runs the other way. Heavy, long, irregular bleeding in your forties is so typical that it is easy — for you and for a busy clinician — to file it under perimenopause and stop thinking. Usually that is correct. But endometrial hyperplasia (a thickened lining that can precede cancer) and endometrial cancer both occur in this age group, and they present in precisely this way. They do not announce themselves with a different symptom.

So the standard is not "panic" and it is not "ignore". It is this: "it's just perimenopause" is a conclusion, not a starting assumption. It should be reached after an assessment, not instead of one. If you are told it is just your age, it is entirely reasonable to ask what has been excluded, and whether your bleeding warrants an ultrasound.

There is a second reason not to wait it out, and it has nothing to do with cancer. Heavy bleeding is one of the most-missed causes of iron deficiency in midlife women. Iron can fall low enough to flatten you long before you are formally anaemic — the exhaustion, the breathlessness on stairs, the brain fog, the hair shedding all get blamed on menopause itself. Ask for a full blood count and a ferritin, by name.

Bleeding on HRT: which regimen are you on?

HRT changes the rules again, and the two main regimens have opposite expectations built into them.

Sequential (cyclical) HRT gives estrogen continuously and progestogen for part of the month. When the progestogen stops, the lining sheds — a withdrawal bleed. A predictable monthly bleed on this regimen is the regimen working as designed. It is not a side effect and it is not a warning. What is worth reporting is a change: bleeding at unexpected times, a bleed that becomes heavy or prolonged, or bleeding that starts appearing in between.

Continuous combined HRT gives both hormones every day and is meant to produce no bleed at all — but it very often bleeds at first. Unscheduled spotting or light bleeding in the first 3–6 months is common and usually settles as the lining adjusts. Two situations change that reading entirely: bleeding still going on past about 6 months, and new bleeding that starts after 6+ months on a stable dose, when you had already settled into no bleeding. Both are investigated rather than waited out — the second one especially, because a lining that had gone quiet and then bleeds is a change that needs an explanation.

One thing this tool will not do, at any stage: tell you to change your HRT. Not the dose, not the type, not the timing — and above all not the progestogen, which is the part that protects the womb lining. Dropping it is the single change most likely to make bleeding worse rather than better. Report what is happening to whoever prescribes it, keep taking it as prescribed, and let them decide. Stopping HRT to "see whether the bleeding stops" does not answer the question; it only makes the picture harder to read.

What an investigation actually involves

People delay because they do not know what they are walking into, so here it is plainly. It usually starts with an examination — a look at the vulva, vagina and cervix, which is often the fastest way to find atrophy or a polyp. Then a transvaginal ultrasound to measure the thickness of the endometrium, the lining of the womb.

In postmenopausal women who are not on HRT, a threshold of around 4 mm is commonly used to decide what happens next: a lining at or below it makes cancer unlikely and a biopsy may not be needed immediately, while a thicker lining leads on to sampling. That threshold does not transfer to women on HRT, whose linings behave differently, and it is a decision aid rather than a verdict. If sampling is needed, an endometrial biopsy takes a small sample of the lining through a thin tube — usually done in clinic, usually a few crampy minutes. Hysteroscopy, a thin camera that looks inside the womb directly, comes next when more detail is needed.

And the caveat that matters more than any of it: a thin lining does not close the question if the bleeding continues. A measurement under the threshold makes cancer unlikely; it does not make it impossible, and it can miss a polyp or a focal patch sitting in one spot that an average thickness simply does not see. A normal scan is a snapshot of that day. If you bleed again afterwards, that is new information — go back and say so, and expect it to be looked into further rather than filed against the old result.

What to take to the appointment

Bring three things: the date of your last real period (it is what defines your stage, and everything downstream depends on it), a rough record of the bleeding — dates, how heavy, how often you changed protection, clots, what set it off — and, if you are on HRT, the exact regimen and how long you have been on it. Then ask: what is the most likely explanation, what else could it be, and what is the plan to assess the lining of my womb?

Go deeper: postmenopausal bleeding, heavy periods in perimenopause, irregular periods in perimenopause, spotting between periods, and estrogen-only vs combined HRT — the regimen you are on decides whether a bleed is expected or not. If dryness is part of the picture, start with vaginal atrophy. To track cycles and bleeding over time, use the period & ovulation tracker, and browse everything we have on menopause.