Uterine polyps are growths of the womb lining that often cause irregular bleeding, though many cause no symptoms at all. Most are benign, and hysteroscopy both confirms the diagnosis and allows removal.
Uterine polyps are one of the more common findings in gynaecology, and one of the more frequently misunderstood. They are usually discovered when a woman is investigated for bleeding that does not fit her usual pattern, and quite often they are found by chance during a scan performed for another reason entirely. Hearing that there is a growth inside the womb is unsettling, which is why it helps to know what these growths actually are.
The great majority of uterine polyps are benign. They can, however, cause troublesome bleeding, they can complicate attempts to conceive, and in a small number of cases, particularly after the menopause, they need proper assessment to rule out something more serious. This guide covers what polyps are, who tends to develop them, how they differ from fibroids, how they are found and removed, what recovery involves, and the one symptom that should never be left.
What Are Uterine Polyps?
A uterine polyp, more precisely called an endometrial polyp, is an overgrowth of the lining of the womb. The endometrium, which thickens and sheds each month, sometimes develops a localised area that keeps growing rather than shedding cleanly. That area projects into the cavity of the womb, carrying its own small blood supply with it.
Polyps vary considerably in size. Some are only a few millimetres across and are barely visible; others grow to several centimetres and can fill much of the cavity. Some sit on a narrow stalk, so that they hang into the cavity and move slightly, while others have a broad base attached directly to the wall. Occasionally a polyp on a long stalk protrudes down through the cervix. There may be a single polyp or several at once.
They are common. Estimates vary depending on the population studied and how carefully anyone looked, but polyps are found in a meaningful minority of women investigated for abnormal bleeding, and in a smaller but significant proportion of women with no symptoms at all. They become more frequent with age through the reproductive years, peaking around the perimenopause and the years just after the menopause.
They are not the same as cervical polyps, which grow from the neck of the womb and are visible during a routine examination, nor are they related to bowel polyps despite the shared name.
What Are the Symptoms of Uterine Polyps?
The most consistent theme is bleeding that does not follow the expected pattern. Because a polyp is made of lining tissue with a fragile blood supply, it bleeds unpredictably and independently of the rest of the endometrium.
Common presentations include bleeding or spotting between periods, periods that have become heavier or longer than they used to be, cycles that have become irregular in length, prolonged spotting at the end of a period, bleeding after sex, and, in women past the menopause, any bleeding at all. Some women notice a brownish discharge rather than frank bleeding.
Pain is not typical. Occasionally a polyp on a long stalk causes cramping as the womb attempts to expel it, but persistent pelvic pain is more likely to have another explanation. If bleeding has been heavy for some time, tiredness and breathlessness from anaemia can be the symptom that finally brings a woman to the clinic.
A significant number of polyps cause no symptoms whatsoever. These are found incidentally during a scan for something else, or during fertility investigations. Being asymptomatic does not automatically mean nothing needs doing, but it does change the balance of the conversation about treatment.
Because irregular bleeding has many possible causes, from hormonal fluctuation to thyroid problems to structural changes, a polyp is one item on a list rather than an assumption. Our article on the causes of irregular periods sets out the wider picture.
Who Is More Likely to Develop Uterine Polyps?
Polyp growth is driven largely by oestrogen, so the risk factors are essentially the circumstances in which the lining is exposed to relatively more oestrogen, or exposed to it for longer without the balancing effect of progesterone.
Age is the strongest single factor. Polyps are uncommon before the twenties, become steadily more frequent through the thirties and forties, and are most often diagnosed in the years around the menopause. In the perimenopause, cycles frequently become anovulatory, meaning ovulation does not occur, and without ovulation there is no progesterone to oppose oestrogen's effect on the lining.
Carrying excess weight raises the likelihood, because fat tissue converts other hormones into oestrogen, adding to what the ovaries produce. This effect continues after the menopause, when body fat becomes the main source of oestrogen in the body.
Tamoxifen, a medication used in the long-term management of certain breast cancers, is a well-recognised factor. It blocks oestrogen in breast tissue but has an oestrogen-like effect on the womb lining, and women taking it are known to develop polyps more often. This is not a reason to stop the medication, but it is a reason for any bleeding to be investigated promptly. Hormone replacement therapy after the menopause, particularly regimens with a relatively higher oestrogen component, is also associated with polyp formation. High blood pressure appears in some studies as an additional factor.
Uterine Polyps vs Fibroids: What Is the Difference?
These two are confused constantly, partly because both are benign growths in the womb, both cause heavy or irregular bleeding, and both are found on ultrasound. The difference lies in what they are made of and where they grow.
A polyp arises from the endometrium, the lining. It is soft, usually small, and grows into the cavity of the womb. A fibroid arises from the myometrium, the muscular wall. It is firm and dense, made of muscle and fibrous tissue, and can grow in several positions: within the wall, bulging outwards from the surface of the womb, or pressing into the cavity.
Size and consequence differ accordingly. Polyps rarely make the womb noticeably larger. Fibroids can grow to considerable size and produce pressure symptoms that polyps essentially never cause: a swollen lower abdomen, needing to pass urine frequently, constipation, backache and a sense of heaviness in the pelvis. Detailed fibroid symptoms are worth reading if pressure symptoms are part of your picture.
Age patterns overlap but are not identical, and fibroids are strongly influenced by family history and ethnicity in a way polyps are not. On ultrasound an experienced eye can usually distinguish them, since a polyp typically appears as a bright, uniform structure within the cavity with a single feeding vessel, while a fibroid appears darker and denser within the wall.
Treatment differs too. A polyp confined to the cavity can be removed through the cervix without any incision. A fibroid within the muscle wall generally requires a different operation. This is why establishing which one you have actually matters, rather than being a technicality.
How Are Uterine Polyps Diagnosed?
Assessment usually starts with a transvaginal ultrasound. This gives a clear view of the womb and can show a polyp as a focal thickening or a distinct mass within the cavity. Timing helps: a scan performed in the first half of the cycle, shortly after a period, is more informative because the lining is thin and a polyp stands out against it. Later in the cycle, when the lining is thick, a small polyp can hide within it. Adding colour Doppler to look for the single feeding blood vessel typical of a polyp improves the picture further. Understanding what the measurement of your endometrial thickness means can be useful when interpreting a scan report.
When the ultrasound is uncertain, saline infusion sonography, sometimes called a sonohysterogram, is often the next step. A small amount of sterile fluid is passed into the cavity through a fine catheter while scanning continues. The fluid separates the walls of the womb and outlines anything projecting into the space, so a polyp that was ambiguous becomes obvious. It is done in the clinic, takes only a few minutes, and typically feels like period cramping.
Hysteroscopy is the definitive investigation. A very thin telescope is passed through the cervix, allowing the inside of the womb to be seen directly. Nothing else shows the number, size, position and appearance of polyps as accurately, and tissue can be taken or the polyp removed during the same procedure. It is often performed in an outpatient setting without general anaesthesia.
One point is worth knowing: an old-fashioned blind curettage, scraping the lining without visualising it, misses polyps regularly, because the instrument can pass straight over a mobile polyp. Direct vision is what makes the difference, which is why hysteroscopic assessment has become the standard approach.
Are Uterine Polyps Cancerous?
This is the question everyone wants answered first, and it deserves a straight response rather than blanket reassurance.
The overwhelming majority of endometrial polyps are entirely benign. Most cause nothing worse than nuisance bleeding, and many would never have caused any trouble had they not been found. That is the honest general picture.
However, a small minority contain abnormal cells. These range from hyperplasia, an overgrowth that is not cancer but can carry a risk of progressing, through to, uncommonly, cancer within the polyp. The likelihood is not the same for everyone, and several features shift it upwards: having gone through the menopause, having bleeding as a symptom rather than being asymptomatic, larger polyp size, and taking tamoxifen. A postmenopausal woman with bleeding and a polyp is in a different position from a thirty-year-old whose polyp was an incidental finding.
This is why removed polyps are always sent for laboratory examination, even when they look completely ordinary at hysteroscopy. Appearance alone cannot exclude abnormal cells, and the tissue analysis is what provides the answer.
The reasonable stance, then, is neither alarm nor dismissal. If you have been told you have a polyp, it is very likely benign. If you are postmenopausal and bleeding, that combination needs proper investigation without delay, not because it is probably cancer but because it is the one scenario in which finding out quickly genuinely matters.
Uterine Polyps and Fertility
Polyps can affect fertility, although the relationship is not absolute and many women with polyps conceive without difficulty.
Several mechanisms are proposed. A polyp occupies space in the cavity where an embryo would implant, and the lining overlying and surrounding it may be less receptive. A polyp sitting near the opening of a fallopian tube may physically interfere with sperm transport or with the passage of the fertilised egg. There is also evidence that polyps alter the local chemical environment of the cavity in ways that make implantation less likely, and irregular bleeding caused by a polyp can make timing intercourse harder.
For these reasons, when a polyp is found during fertility investigations, removal is commonly recommended before proceeding with treatment, and many clinics will check the cavity carefully before embryo transfer. The procedure is straightforward, the cavity heals quickly, and conception is usually possible within a short time afterwards. If you are undergoing fertility investigation, it is reasonable to ask whether your uterine cavity has been properly assessed rather than only your ovaries and tubes.
Polyps have also been raised as a possible factor in recurrent miscarriage, though the evidence there is less settled. As with much of fertility medicine, the decision is individual, weighing the size and position of the polyp against your history and how long you have been trying.
Treatment Options: Watchful Waiting or Removal
Not every polyp needs to come out, and the decision rests on your symptoms, your age, your menopausal status and whether you are trying to conceive.
Observation is reasonable for small polyps, generally under about a centimetre, that cause no symptoms in a woman who is still having periods and is not trying to conceive. Small polyps quite often regress on their own, particularly in younger women, as the lining sheds each month. The usual approach is a repeat scan after several months to see whether it has grown, shrunk or disappeared.
Removal is generally advised when a polyp is causing bleeding that bothers you, when it is large, when you are trying to conceive or about to undergo fertility treatment, when you are postmenopausal, or when you are taking tamoxifen. Postmenopausal polyps are usually removed rather than watched, because the tissue diagnosis is more important in that group.
Medication has a limited role. Hormonal treatment can reduce bleeding while a polyp is present and may thin the lining generally, but it does not reliably make a polyp disappear, and once it is stopped symptoms tend to return. Hormonal management is therefore usually a way of controlling bleeding rather than a substitute for removal when removal is indicated.
It is worth asking, when a plan is proposed, what the specific reason is: to relieve symptoms, to obtain a tissue diagnosis, to improve the chance of implantation, or a combination. That framing makes the decision much easier to weigh.
What Hysteroscopic Polypectomy Involves and Recovery
Hysteroscopic polypectomy means removing the polyp through the cervix using a hysteroscope, with no cuts to the abdomen. It is the standard approach and has largely replaced blind procedures.
What happens is broadly this. Depending on the size and number of polyps and your own preference, it may be done in an outpatient clinic with no anaesthetic or a local anaesthetic to the cervix, or as a day case under sedation or general anaesthesia. The cervix may need gentle dilation, and a medication is sometimes given beforehand to soften it. The hysteroscope is passed into the womb, and fluid is used to open the cavity so that the surgeon can see clearly. The polyp is then removed, using fine scissors, grasping forceps, an electrosurgical loop or a small mechanical device that cuts and suctions the tissue at once. The base is dealt with so that as little tissue as possible is left behind. The removed tissue is sent for laboratory examination. Most procedures take somewhere between ten and thirty minutes.
Recovery is usually quick. Expect period-like cramping for a day or two, which normally responds to simple painkillers, and light bleeding or brownish discharge for anything from a few days up to a couple of weeks. If you had no anaesthetic, you can generally go home shortly afterwards and return to normal activities the same or next day. After sedation or general anaesthesia, you will need someone to take you home and should plan to rest for the remainder of the day.
You will usually be advised to avoid tampons, swimming, baths and sex until bleeding has stopped, typically about a week, to reduce the risk of infection. Contact your doctor if you develop a fever, offensive-smelling discharge, heavy bleeding that soaks through protection quickly, or severe pain that is not relieved by painkillers. Serious complications are uncommon, but they include infection, perforation of the womb and, rarely, scarring within the cavity. Your next period may come slightly earlier or later than expected, and the first one or two cycles can be a little different before settling.
Can Uterine Polyps Come Back?
Yes. Recurrence after removal is possible, and it happens often enough that it is worth knowing in advance rather than being surprised by it.
Whether a polyp returns depends partly on technique and partly on circumstances. Complete removal including the base under direct vision is less likely to be followed by recurrence than incomplete removal. Beyond that, the same conditions that produced the first polyp remain: if you are perimenopausal with anovulatory cycles, carrying excess weight, taking tamoxifen or on hormone replacement therapy, the hormonal environment that encouraged the first growth has not changed.
Having multiple polyps at the first procedure also makes recurrence more likely than having a single one. Women on tamoxifen are usually followed with this in mind.
Recurrence is not a sign that something went wrong, and it does not mean the original procedure failed. It is simply that the tissue is inclined to behave the same way again. In some situations, particularly for women who have completed their families and have repeated symptomatic polyps, a hormone-releasing intrauterine device may be discussed as a way of keeping the lining thin. The practical takeaway is that if abnormal bleeding returns months or years after a polypectomy, it should be reported rather than assumed to be dealt with.
When to See a Doctor
Some bleeding patterns can be watched, and some should be assessed without delay. The clearest rule concerns the menopause.
Any bleeding after the menopause, defined as more than twelve months since your last period, needs medical assessment. This applies to a single episode of spotting, to a pink or brown stain, to bleeding you can explain by something you did, and to bleeding you are certain is nothing. Most postmenopausal bleeding turns out to have a benign cause, and a polyp is one of the more frequent findings. But it is also the way endometrial cancer most commonly presents, and it is highly treatable when caught early. There is no version of this in which waiting is the better choice.
Before the menopause, arrange an appointment if you bleed between periods, if you bleed after sex, if your periods have become noticeably heavier or longer than they used to be, if you are spotting for several days before or after each period, if you have unexplained brownish discharge, or if you have been trying to conceive for a year without success. Also seek advice if heavy bleeding is leaving you tired, breathless or lightheaded, since anaemia may need treating alongside the underlying cause.
A general gynaecological assessment is also reasonable if you are on tamoxifen or hormone replacement therapy and notice any change in your bleeding pattern, since a change in pattern is the signal that matters most in both situations.
Uterine polyps are, for most women, a manageable and benign problem with a straightforward solution. What they should never be is a reason to normalise bleeding that is not normal for you. Abnormal bleeding is information, and it is worth acting on.
References
This article was prepared with reference to the following independent health sources.
- NHS. Hysteroscopy
- NHS. Womb (uterus) cancer
