Sexual wellbeing
Endometrial Thickness Interpreter
Got an endometrial thickness — the "stripe" in millimetres from a transvaginal ultrasound — you don't understand? Enter it and pick your situation. The number only means something in context: after menopause with bleeding a stripe of 4 mm or less is reassuring on that scan, but the same number means something else without bleeding, and premenopausal thickness has no single cutoff. Everything is interpreted on your own device.
A thin stripe does not rule out cancer if bleeding after menopause keeps happening — persistent bleeding needs evaluation whatever the number. This tool explains a measurement; it's never a diagnosis.
Endometrial thickness interpreter
The 4 mm threshold applies only to postmenopausal bleeding, and even then a thin stripe doesn't rule out cancer if bleeding continues. There's no single premenopausal cutoff. A measurement isn't a diagnosis — discuss your report with the gynecologist who ordered the scan.
How to read it
The 4 mm threshold — and where it does and doesn't apply
After menopause, estrogen falls and the uterine lining should normally be thin. That's what makes the endometrial stripe useful when a postmenopausal woman has bleeding: ACOG's guidance (Committee Opinion 734) is that a thickness of 4 mm or less has a greater than 99% negative predictive value for endometrial cancer — so transvaginal ultrasound is a reasonable first step, and a thin stripe often means a biopsy can be deferred. A stripe above 4 mm doesn't diagnose anything on its own, but it's thick enough that the tissue should be sampled and looked at.
Two limits matter enormously. First, this cutoff is for bleeding after menopause — it is not validated for a thickened lining found by chance in someone with no bleeding, and it has no meaning before menopause. Second, and most important: a thin stripe is not an all-clear if the bleeding keeps happening. ACOG states that persistent or recurrent postmenopausal bleeding should prompt tissue evaluation regardless of thickness. Here's how the bands read in the postmenopausal-bleeding setting:
| Stripe (with bleeding) | What it generally means | Usual next step |
|---|---|---|
| 4 mm or less | A thin stripe. In a postmenopausal woman with bleeding, a thickness of 4 mm or less has a greater than 99% negative predictive value for endometrial cancer — the reassuring direction on that scan. | Often no immediate biopsy. But if bleeding persists or comes back, tissue evaluation is still needed regardless of the number — a thin stripe does not rule cancer out when bleeding continues. |
| More than 4 mm | Above the threshold ACOG uses. This does not mean cancer — the most common cause of postmenopausal bleeding is a thin, atrophic lining — but the stripe is thick enough that the tissue itself should be looked at. | Endometrial sampling (a biopsy), sometimes with saline-infusion sonography or hysteroscopy, is the usual next step so a clinician can see what the lining is made of. |
The 4 mm figure is the established threshold from ACOG Committee Opinion 734, and only for postmenopausal bleeding. It is not a pass/fail line without bleeding or before menopause, and no value here is a diagnosis.
For context
A thick lining with no bleeding — different rules
Sometimes a thickened endometrium turns up on a scan done for another reason, in a postmenopausal woman with no bleeding at all. This is a genuinely different situation. The 4 mm threshold was studied in women who have bleeding, so applying it mechanically to an incidental finding isn't appropriate — and ACOG notes there's no evidence to support routine ultrasound screening of the endometrium in women without symptoms.
What that means in practice: an incidentally thickened lining is weighed against your individual risk factors — not against a single millimetre cutoff — and a gynecologist decides whether anything further is warranted, and whether the measurement is even reliable. It's a reason for a considered conversation, not alarm. The one thing that clearly changes the picture is new bleeding: any bleeding after menopause should be evaluated promptly, and that's exactly what our bleeding checker helps you think through.
For context
Before menopause, the lining is meant to change — so there's no single number
If you're still having periods, your endometrium rebuilds and sheds every cycle, so its thickness is a moving target. A stripe measured just after a period and one measured just before the next can look completely different and both be normal. That's why there is no single premenopausal cutoff — the number has to be read against where you are in your cycle and your symptoms, not against a fixed line. We show the direction, not fabricated per-phase millimetres:
| Where you are in your cycle | The lining is | What that means |
|---|---|---|
| Just after your period | Thinnest | The lining has recently shed, so the stripe reads at its lowest for the cycle. |
| First half (before ovulation) | Thickening | Rising estrogen rebuilds the lining, so the stripe grows steadily day by day. |
| Around ovulation | Layered look | The lining often takes on a distinct three-line ("trilaminar") appearance mid-cycle. |
| Second half (before your period) | Thickest | After ovulation the lining is at its fullest, ready to either support a pregnancy or shed. |
A general direction, not diagnostic numbers. What's worth taking to a clinician before menopause is abnormal bleeding — between periods, much heavier than usual, or after sex — rather than the millimetre reading alone.
Read this before you read too much into it
A thin stripe is reassuring — it is not an all-clear
The most important thing this tool can tell you is what a low number doesn't mean. In a postmenopausal woman with bleeding, a stripe of 4 mm or less makes endometrial cancer very unlikely on that scan — but ACOG is explicit that persistent or recurrent bleeding should prompt tissue evaluation regardless of thickness, because rare aggressive cancers can present even when the stripe is thin. So if bleeding after menopause keeps happening, a thin lining is not a reason to stop looking. Any bleeding after menopause deserves a clinician's assessment; bleeding that continues deserves it again.
Two more limits. The 4 mm cutoff is only for bleeding after menopause — it doesn't apply to an incidental thickened lining with no bleeding, and it has no meaning before menopause, where thickness swings across every cycle. And the measurement itself can be affected by fibroids, polyps, hormone therapy, or a lining that's hard to see clearly. This tool interprets a number in plain language and routes you to a gynecologist — it never diagnoses, and it is never the reason to wait on symptoms that need care.
Next steps
Related tools
Bleeding checker
The symptom side: think through what bleeding pattern you have and whether it needs to be checked — what a millimetre reading can't tell you.
Menopause symptom score
Gauge how much menopause symptoms are affecting you, and where a clinician conversation fits.
FSH menopause interpreter
Read an FSH blood result against menopause context — another lab number explained, not diagnosed.
All sexual health tools
The full suite of private, in-browser checkers and calculators.
Sources
Where this comes from
The postmenopausal-bleeding framing follows ACOG Committee Opinion 734: a transvaginal endometrial thickness of 4 mm or less has a greater than 99% negative predictive value for endometrial cancer, while persistent or recurrent bleeding warrants histologic evaluation regardless of thickness, and there's no evidence for routine screening of asymptomatic women. MedlinePlus provides the plain-language note that bleeding after menopause may lead to a biopsy and/or vaginal ultrasound; RadiologyInfo.org (RSNA/ACR) explains what a transvaginal ultrasound of the endometrium is. We apply that guidance and keep the premenopausal and no-bleeding contexts qualitative — we don't invent per-millimetre cutoffs where none are established. Interpretation of your actual result belongs with the gynecologist who ordered the scan.
Medically Reviewed & Fact-Checked · Updated
Reviewed by EasySTD Editorial Team
Compiled and checked by EasySTD's editorial team against CDC and public-health sources. This is educational information, not a substitute for advice from a licensed clinician. Our editorial guidelines →
3 Sources
Data & references
- ACOG Committee Opinion No. 734: The Role of Transvaginal Ultrasonography in Evaluating the Endometrium of Women With Postmenopausal Bleeding (2018)https://www.acog.org/clinical/clinical-guidance/committee-opinion/articles/2018/05/the-role-of-transvaginal-ultrasonography-in-evaluating-the-endometrium-of-women-with-postmenopausal-bleeding
- MedlinePlus: Menopause (vaginal bleeding after menopause — biopsy and/or vaginal ultrasound)https://medlineplus.gov/ency/article/000894.htm
- RadiologyInfo.org (RSNA/ACR): Ultrasound — Pelvis (transvaginal ultrasound of the endometrium)https://www.radiologyinfo.org/en/info/pelvus
EasySTD is an information and comparison directory, not a healthcare provider. This tool is general information based on published guidance: it is not medical advice, a diagnosis, or an all-clear, and it does not create a doctor-patient relationship. A single measurement isn't definitive and can be affected by timing, hormones, and image quality — discuss your result with a gynecologist, who reads it against your history and symptoms. Any bleeding after menopause should be evaluated; heavy bleeding, feeling faint, or severe pain is urgent — seek care straight away.
Good to Know
Endometrial thickness: frequently asked questions
What the endometrial stripe is, what a 4 mm-or-less reading means with bleeding (and why it's still not an all-clear), what a thick lining means with and without bleeding, why there's no single premenopausal cutoff, and how your data stays private.
What is the "endometrial stripe" and what does its thickness mean?
The endometrial stripe is the bright line an ultrasound sees where the two layers of your uterine lining (the endometrium) meet — and its thickness, measured in millimetres on a transvaginal scan, is a rough gauge of how built-up that lining is. On its own the number is just a measurement: what it means depends entirely on your situation. After menopause the lining should normally be thin because estrogen has dropped, so a thicker stripe there is worth explaining. Before menopause the lining is supposed to thicken and thin dramatically every cycle, so the same number can be completely normal. That's why this tool asks for your context first — a thickness that would prompt a biopsy in one situation is unremarkable in another. It reads the number for you in plain language; the clinician who ordered the scan interprets it against your full picture.
I'm postmenopausal with bleeding and my stripe is 4 mm or less — does that rule out cancer?
It's strongly reassuring about that scan, but it is not a guarantee, and this distinction matters. ACOG's guidance (Committee Opinion 734) is that in a postmenopausal woman with bleeding, an endometrial thickness of 4 mm or less has a greater than 99% negative predictive value for endometrial cancer — so a thin stripe makes cancer very unlikely and often means a biopsy can be deferred at that moment. What a thin stripe cannot do is rule cancer out if the bleeding keeps happening. ACOG is explicit that persistent or recurrent postmenopausal bleeding should prompt a histologic (tissue) evaluation regardless of endometrial thickness, because rare aggressive cancers can present even when the stripe is thin. So the number is good news about the picture today, not a reason to ignore bleeding that continues. Any bleeding after menopause deserves a clinician's eyes; ongoing bleeding deserves them again.
My postmenopausal stripe is thicker than 4 mm — do I have cancer?
No — a thick stripe is not a cancer diagnosis, and most of the time it is not cancer. The single most common cause of postmenopausal bleeding is a thin, atrophic lining, and thickened readings are frequently caused by benign things like polyps, fibroids, hormone (including tamoxifen) effects, or simply a lining that is fuller than expected. What a thickness above 4 mm does mean is that the stripe is thick enough that the tissue itself should be examined rather than assumed benign. The usual next step is endometrial sampling — a biopsy — sometimes alongside saline-infusion sonography or hysteroscopy to get a clearer view. Think of a thick stripe as a reason to look, not a verdict. Bring the report to a gynecologist, who will decide which of those steps fits your situation and your risk factors.
I'm postmenopausal but I'm NOT bleeding, and my scan mentioned a thick lining — should I worry?
The reassuring news is that the well-known 4 mm cutoff was studied in women who have bleeding, and it does not automatically apply to a thickened lining found by chance in someone with no bleeding. ACOG notes there is no evidence to support routine ultrasound screening of the endometrium in asymptomatic postmenopausal women, and an incidentally discovered thickened stripe with no bleeding is managed by weighing your individual risk factors — not by mechanically applying the bleeding threshold. That means the right response is a conversation, not a panic: a gynecologist decides whether the finding needs anything further based on things like your risk profile, hormone use, and the appearance of the lining, and whether the measurement is even reliable. What matters most is this: if bleeding does start after menopause, that changes everything and should be evaluated promptly.
Why is there no single "normal" endometrial thickness before menopause?
Because before menopause the lining is designed to change constantly. Every cycle, rising estrogen rebuilds and thickens the endometrium in the first half, it reaches its fullest after ovulation, and then it sheds as a period — so the stripe is at its thinnest just after you bleed and at its thickest just before your next period. A reading taken on day 5 and one taken on day 24 can look completely different and both be perfectly normal. On top of that, the number is affected by where you are in your cycle, whether you're on hormonal contraception, and normal person-to-person variation. That's why no single premenopausal cutoff exists, and why this tool won't hand you a pass/fail number for that context — it can only be read against your cycle timing and your symptoms. If you have bleeding that's abnormal for you — between periods, much heavier, or after sex — that's the thing worth taking to a clinician, not the millimetre reading alone.
Is what I enter here private?
Yes. This tool runs entirely in your browser: the thickness, situation, and any symptoms you enter are interpreted on your own device and are never sent to a server, saved, or shared — close the tab and they're gone. There's no account and nothing to delete, and we treat gynecologic-health information as sensitive by default. What you see is general educational information based on published guidance from ACOG, MedlinePlus, and RadiologyInfo.org; it isn't medical advice, a diagnosis, or an all-clear, and it can't replace the gynecologist who ordered your scan and reads it against your full history. If you have heavy bleeding, feel faint, or have severe pain, treat that as urgent and seek care straight away, whatever the number says.
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