Endometrial Polyps: Bleeding Between Periods, and What Actually Needs Removing

A great many women are told, after months of spotting between their periods, that their scan was fine, their biopsy was normal, and there is nothing to find. Some of them have a polyp.

An endometrial polyp is a small overgrowth of the lining of the uterus — a soft tag of tissue on a stalk, growing into the cavity. Most are a few millimetres to a couple of centimetres across. Most are entirely benign. And most of the trouble they cause is not dramatic: it is a bit of bleeding at the wrong time of the month, month after month, that nobody quite gets to the bottom of.

This page is about what polyps really do, how they are properly diagnosed, and — the part that matters most — which ones genuinely need removing and which can be left alone.

What is an endometrial polyp, exactly?

The endometrium is the lining that thickens each month and sheds as your period. A polyp is a focal area of that lining that keeps growing where the rest does not, forming a small fleshy projection into the uterine cavity, usually attached by a narrow stalk carrying its own blood vessel.

Because it has its own blood supply and does not shed neatly the way the rest of the lining does, it tends to bleed on its own schedule. That is the whole story of the symptoms.

Polyps can be single or multiple, a few millimetres or several centimetres. They are not fibroids — a fibroid is a muscle growth in the wall of the uterus, a polyp is a lining growth inside the cavity. The two behave differently and are treated differently, which is why the decision about fibroid surgery follows quite different rules.

How common are they?

Common enough that you should not feel singled out.

• Around 12% of women before menopause have an endometrial polyp with no symptoms whatsoever.
• Among women investigated for abnormal bleeding, polyps turn up in roughly 8% to 22% of cases.
• Among women being investigated for difficulty conceiving, the figure is higher — 16% to 32%. In one series of 1,000 women having hysteroscopy before IVF, 32% had a polyp.

They are most often found between the ages of 40 and 49, and the chance of having one rises steadily with age until menopause.

What symptoms does a polyp actually cause?

Here is the part most articles get slightly wrong.

The symptom most characteristic of a polyp is bleeding at the wrong time — spotting or bleeding between periods, brown discharge mid-cycle, bleeding after sex, or an unpredictable pattern that does not fit your usual cycle.

Notice what is not on that list: pain. Polyps are usually painless. Occasional cramping can happen if the uterus is trying to expel one, but pain is not their signature, and pain with a polyp on the scan should make your doctor look for a second explanation.

Do polyps cause heavy periods?

They can — but I want to be honest about the strength of the evidence, because it is more nuanced than most patient information admits.

Polyps are one of the recognised structural causes of abnormal uterine bleeding, and after polyp removal, abnormal bleeding improves in the large majority of women. But when researchers actually randomised 150 women with polyps either to have them removed or to wait six months, and then measured the volume of menstrual blood loss, the two groups did not differ on how heavy the periods were. What improved significantly was the bleeding between periods.

That fits exactly what polyps do. So if your main problem is genuinely heavy flooding periods, a polyp on your scan may not be the whole answer, and the search should continue — fibroids, adenomyosis and a thickened lining are the usual bigger culprits. Our guide to heavy and irregular periods and when to consider surgery works through that whole list and the operations that go with each cause.

If your problem is spotting between periods, a polyp is one of the first things I would want to exclude.

Why do polyps form, and who gets them?

The honest answer is that we do not fully know. Polyps appear to grow in areas of lining that are unusually sensitive to oestrogen and that fail to shed properly. What we do know is which women get them more often:

• Age — the strongest single factor, peaking in the forties.
• Higher body weight — fat tissue produces oestrogen, and the lining is exposed to more of it.
• PCOS — irregular or absent ovulation means the lining is exposed to oestrogen without the monthly progesterone that would normally shed it cleanly. If you have PCOS and irregular bleeding, this is worth knowing.
• Diabetes and high blood pressure — both are associated with a higher chance of having a polyp.
• Tamoxifen, taken after breast cancer — a well-recognised and much stronger association. Polyps are found in a substantial minority of long-term users.
• Never having been pregnant.

None of these are things you did wrong. They are the reasons the lining had more oestrogen exposure and fewer clean sheds, over years.

Are endometrial polyps cancerous?

This is the question everybody actually came here for, so let me give you the numbers rather than reassurance.

The largest analysis pooled 51 studies and more than 35,000 women who had polyps removed and examined under the microscope. Across all of them, 2.7% contained a cancer. But that single figure hides everything that matters, because the risk splits sharply:

Put those together and you get the rule that actually guides practice: a postmenopausal woman with a polyp and bleeding sits at roughly 4 to 5%, while a postmenopausal woman whose polyp was found incidentally sits closer to 1.5%. The bleeding, not the polyp, is doing most of the work in that number.

Does the size of the polyp decide anything?

Less than you would expect, and the evidence genuinely conflicts.

In one careful study of 240 postmenopausal women, polyps of 13 mm or less carried about a 2% risk of pre-cancer or cancer, while those above 13 mm carried about 19%. That looks decisive. But a separate study of 472 asymptomatic postmenopausal women tested cut-offs at 10, 15 and 20 mm and found no size threshold that reliably separated the safe from the unsafe.

My reading of that, and how I put it to patients: size shifts the odds, particularly after menopause, and a large polyp is a reasonable additional reason to remove one. But size is not a rule, and no measurement on a scan report can tell you what a polyp is made of. Only the microscope can do that. This is the same principle that governs fibroid surgery and ovarian cysts: the number is one input, never the decision.

How is a polyp properly diagnosed?

There is a right order to this, and getting it right saves months.

"My biopsy was normal" — does that rule out a polyp?

No. And this is the single most useful thing on this page.

A blind endometrial biopsy — a pipelle sample taken in the clinic without a camera, or an old-fashioned D&C — scrapes or suctions the lining generally. A polyp is focal, mobile and on a stalk. It slides away from the instrument. Compared against biopsy taken under direct hysteroscopic vision, blind sampling detects somewhere between 8% and 46% of polyps. Which is to say it misses more than half, and sometimes far more.

This is not a fringe view. The UK's NICE guidance on heavy menstrual bleeding states plainly: obtain an endometrial sample only in the context of diagnostic hysteroscopy, and do not offer blind endometrial biopsy. The AAGL guideline on polyps says the same: blind dilatation and curettage or biopsy should not be used to diagnose an endometrial polyp.

So if you have persistent bleeding between periods, or bleeding after menopause, and you have been reassured by a normal pipelle biopsy alone, that reassurance is weaker than it sounds. The question worth asking is: "has anyone actually looked inside my uterus?"

Will a polyp go away on its own?

Sometimes — and the honest answer is that we cannot predict which.

Estimates of spontaneous regression range from about 6% to about 27%, depending on how long women were followed and who was studied. The largest study to follow expectantly managed polyps found only 6.3% disappeared over a median of more than two years, and, notably, found no relationship between the size of a polyp and whether it shrank, grew or vanished. Smaller studies have found higher regression rates, particularly for polyps under 10 mm.

The reasonable summary is that a minority resolve, small ones probably more often, and nobody can tell you in advance whether yours is in that minority. A watchful approach with a repeat scan is entirely legitimate — it is simply not the same as being told it will go away.

Does every polyp need removing?

No, and I think this deserves saying clearly, because the reflex in a lot of practice is to remove everything found.

There is no medicine that reliably makes a polyp disappear. Hormonal treatment is sometimes tried, and a Mirena-type hormonal coil may make regression somewhat more likely, but the guidelines are clear that medical treatment cannot currently be recommended as a way of treating polyps.

What does polyp removal actually involve?

The operation is called a hysteroscopic polypectomy, and it is one of the gentlest procedures in gynaecology.

A thin telescope goes through the cervix — no cuts, no stitches, nothing through the abdominal wall. The polyp is seen directly and removed at its base, either with a small mechanical cutting device or with a fine electrical loop. In fertility patients, techniques that avoid heat are preferred, to protect the surrounding lining. The whole thing usually takes a matter of minutes, and most women go home the same day.

Two points that matter more than they sound:

• It must be done under vision, not blind. When polyps are removed by blind curettage, a great deal is left behind — one comparison found 27% of women had a polyp again within six months after D&C, against 1.5% after hysteroscopic removal. Most of that difference is not recurrence. It is residue.
• Everything removed goes to the laboratory. This is the part of the operation that answers the cancer question, and it is not optional.

Hysteroscopic polypectomy sits in the same family as the other cavity procedures described in our guide to surgery for heavy periods, and it is by some distance the smallest of them. You can read more about hysteroscopy and what the procedure involves.

Awake in the clinic, or asleep in theatre?

Both are legitimate, and the trade-off is worth understanding before you choose.

A large randomised trial of 507 women compared outpatient polypectomy, done awake, with the same operation under general anaesthesia. Six months later, 73% of the awake group and 80% of the asleep group rated their bleeding as successfully treated — close enough to be considered equivalent. But the trial found two real differences: the polyp was not completely removed in 19% of awake procedures against 7% under anaesthesia, and women rated the awake procedure as less acceptable.

Done well, an awake procedure is very tolerable. A large Indian series of 3,000 office hysteroscopies reported a 98.7% success rate with a single complication across the whole series. Technique, gentle pressure and unhurried counselling make most of the difference.

My own approach is to make it a conversation rather than a policy. A small, accessible polyp in a woman who has had children often suits an awake procedure. A large polyp, several polyps, a narrow cervix, or a woman who would simply rather not be present for it — those are good reasons to do it under anaesthesia and do it properly in one go.

Polyps and getting pregnant

This is where the evidence is at its most encouraging.

The landmark trial randomised 215 women with infertility and a polyp either to have it removed or to have a diagnostic hysteroscopy with only a biopsy, and then gave both groups intrauterine insemination. 63% of the polypectomy group conceived, against 28% of the control group — more than double. Strikingly, 65% of those pregnancies happened before the first insemination cycle even began. Removing the polyp, in other words, was the treatment.

The guidance that follows from this is reasonably consistent:

• If you are trying naturally and a polyp is found, removal is worth considering — the evidence is weaker here than for insemination, but it points the same way.
• If you are about to start IVF, removing a polyp beforehand is generally recommended.
• If a polyp is found during ovarian stimulation, current fertility guidance suggests that one above 20 mm is a reason to freeze the embryos, remove the polyp, and transfer later; below 20 mm, going ahead with a fresh transfer is reasonable if there are no other concerns.
• After polypectomy, a frozen transfer is best done within about four months.
• With recurrent implantation failure or recurrent miscarriage, removal is preferred.

One honest caveat: a Cochrane review concluded that there is still no adequately designed randomised trial of polyp removal before fertility treatment in general, and a large trial of routine hysteroscopy in women with repeated IVF failure found no improvement in live birth. Removing a polyp that is there is well supported. Looking inside everybody's uterus on principle is not.

Can polyps come back?

Yes, but far less often than people fear when removal has been done properly.

After hysteroscopic removal, recurrence runs at roughly 3% even over nine years of follow-up. It is higher — up to around 10% — when there were multiple polyps to begin with, or when the polyp showed hyperplastic change.

Where recurrence is a concern, a hormonal coil helps: in a study of more than 1,100 women, recurrence within a year was 13.6% after polypectomy alone against 5.2% when a hormonal intrauterine system was fitted at the same time. And for women taking tamoxifen, the evidence from randomised trials is clear that a hormonal coil substantially reduces the formation of polyps in the first place — a conversation worth having with your oncologist as well as your gynaecologist.

Bleeding after menopause: please do not wait

I want to end the clinical part of this here, because it is the scenario where delay does the most harm.

Any bleeding after menopause — a single episode, a smear of brown, anything — needs assessing. Most of the time the cause is benign, and a polyp is one of the commoner benign answers. But this is the presentation in which endometrial cancer shows itself, and it is highly curable when it is caught early.

What proper assessment looks like: an examination, a transvaginal ultrasound measuring the thickness of the lining, and — if there is any doubt, a thickened lining, or a focal lesion — a hysteroscopy with tissue sent for histology. Not a pipelle biopsy on its own, for all the reasons above.

Getting this sorted in Gurugram

To be straightforward about what happens where: assessment, examination and the decision-making happen at the clinic. Scans are arranged by referral to a trusted imaging centre, and hysteroscopy and polypectomy are done at hospital, where the equipment and, if you want it, the anaesthesia are available.

What I would want for you at a first appointment is simple — a proper history of exactly when you bleed, an examination that includes the cervix, and a scan arranged at the right point in your cycle so it can actually see what it is looking for. If a polyp is found, the conversation after that is about whether it explains your symptoms, whether it needs to come out now, and what your own priorities are, including fertility.

Our two clinics — Sector 51 (Mayfield Garden) and Sector 56 — see patients from across Gurugram, Golf Course Road, Golf Course Extension, Sohna Road, the DLF Phases, South Delhi and nearby NCR, 7 days a week including Sundays. Where a procedure is needed it is carried out at NABH-accredited hospitals in Gurugram. You can read more about the range of gynaecological surgery we provide.

The bottom line

Endometrial polyps are common, usually harmless, and usually easy to deal with. Before menopause, the chance of one being cancerous is around 1%. After menopause, with bleeding, it is closer to 5% — still low, but high enough that it deserves a tissue answer rather than reassurance.

If you take one thing away, make it this: a normal blind biopsy does not exclude a polyp. If you have been bleeding between your periods for months, or bleeding after menopause, and nobody has looked inside your uterus, the investigation is not finished.

And if a polyp is found, the decision is not automatic. A small silent polyp before menopause can often be watched. A polyp causing you to bleed, or found after menopause, or standing between you and a pregnancy, is usually worth removing — through a procedure that involves no cuts, no stitches, and an afternoon of your life.