Endometrial Polyps (Polyps Inside the Womb)

What is an endometrial polyp, and how common is it?

An endometrial polyp (a polyp that grows from the lining of the womb) forms when the glands and supporting tissue of the lining that covers the inside of the womb gather around a blood vessel and overgrow. They are structures that reach into the cavity of the womb and are usually benign.

• Shape: a polyp may hang from the wall of the womb on a thin stalk (pedunculated) or sit on the wall with a broad base (sessile).
• Number: there may be one or more than one.

Polyps are quite common in women: the overall rate is about 8–35%. In women with abnormal uterine bleeding (bleeding outside the usual cycle or heavier than expected), the rate at which a polyp is found rises to 10–40%.

Risk factors

The main factors that increase the likelihood of a polyp are:

• Age: polyps become more common with age; they are most often found between 40 and 50, in the years around the menopause and after the menopause.
• Use of tamoxifen: this medicine, used to treat breast cancer or to lower the risk of it, has an effect on the lining of the womb similar to oestrogen (the main female hormone) and clearly increases the risk of polyps.
• Excess weight: oestrogen made in fat tissue stimulates polyp growth.
• High blood pressure and diabetes: these are counted among the independent risk factors.
• Hormone use and inherited conditions: being under the effect of oestrogen for a long time without a balancing hormone, use of tibolone (a hormone-like medicine used in the menopause), and Lynch and Cowden syndromes (inherited conditions that raise the tendency to cancer) increase the risk.

Symptoms

A large share of polyps — about 12–50% — cause no complaints at all and are noticed by chance during a gynaecological ultrasound. When there are symptoms, the most common complaint is abnormal uterine bleeding; it is present in 50–88% of women with symptoms:

• Spotting or bleeding between two periods,
• Heavier or longer periods,
• Bleeding after sex,
• Bleeding after the menopause: polyps are responsible for about 25–38% of bleeding seen after the menopause. For the other causes of postmenopausal bleeding and how it is assessed, see Irregular and Abnormal Bleeding.

Less often, cramp-like pain, period pain or vaginal discharge may occur. In women who want a child, a polyp may also be linked to difficulty getting pregnant (explained below).

How is the diagnosis made?

• Transvaginal ultrasound (ultrasound done through the vagina): this is the first-step examination. The polyp appears as a round or oval mass with clear borders, or as a local thickening, in the cavity of the womb. Seeing a single supplying blood vessel entering the stalk of the polyp on colour Doppler (ultrasound that shows blood flow) supports the diagnosis.
• Saline ultrasound (ultrasound done after sterile saline is placed inside the womb; also called sonohysterography): sterile saline is given into the womb through a thin tube passed through the cervix (the neck of the womb); as the cavity of the womb widens, ultrasound is done at the same time. It shows the size and stalk of the polyp and its relation to the wall of the womb with a sensitivity of 88–95%, and helps tell a polyp apart from a fibroid (a benign lump growing from the muscle of the womb).
• Hysteroscopy (viewing the inside of the womb with a camera): the inside of the womb is looked at directly with a thin camera passed through the cervix. Guidelines regard it as the main method for diagnosing polyps. An important advantage is that the polyp can be removed in the same session as soon as it is seen. For details see Hysteroscopy.

The limit of blind sampling: taking a sample blindly with a thin cannula (a flexible thin tube) during an examination, or a classic curettage (scraping the inside of the womb), can miss polyp tissue that can move inside the womb. In 50–75% of cases only the thin surrounding tissue may be sampled without the polyp being touched at all. For this reason, a polyp is removed under direct vision.

Can a polyp be cancer?

Most polyps are benign (not cancer). The likelihood of finding cancer or a precancerous cell change (atypia) inside a polyp differs mainly according to menopausal status and whether there is bleeding:

• Before the menopause: in women of reproductive age this risk is extremely low — about 1–2%.
• After the menopause: in polyps found in this period the risk is clearly higher: 3–13% (on average 5.4%).
• In polyps that bleed (with symptoms) the risk of cancer or a precancerous change is about 4.5–5.1%.
• In polyps that never bleed and are found by chance (without symptoms) this likelihood is as low as 0.2–1.5%.

Other factors that increase the risk: being over 60, a polyp larger than 1.5 cm, use of tamoxifen, excess weight and high blood pressure.

Who can be watched, and who should have the polyp removed?

Not every polyp needs to be removed. Small polyps without symptoms may shrink and disappear on their own over time: follow-up studies have reported that about 27% of polyps without symptoms disappear on their own within a year, and that this rate rises to 50% for those smaller than 1 cm.

When watching may be suitable

In women who have all of the following features, waiting with an ultrasound check every 6–12 months (a watch-and-wait approach) may be a suitable option:

• Being before the menopause,
• Having no complaints such as bleeding or pain,
• The polyp being small (smaller than 1–1.5 cm),
• No additional risk factor for cancer and no problem related to wanting a child.

When removal of the polyp is recommended

1. All women with symptoms who have abnormal bleeding or spotting,
2. All polyps found after the menopause (because of the cancer risk),
3. Women who have difficulty getting pregnant, and before insemination or IVF treatment,
4. A polyp larger than 1.5 cm,
5. Bleeding or a suspicious finding in women using tamoxifen.

Diagnosis and follow-up of endometrial polyps are carried out at the practice in Muratpaşa, Antalya.

Hysteroscopic polypectomy: how is a polyp removed?

Polypectomy (removal of the polyp) is done by hysteroscopy, that is, by looking inside the womb and under direct vision. No cut is made in the abdomen.

How is the procedure done?

The cervix is gently widened and the camera is passed into the womb. The polyp is seen directly and is cut together with its root and removed whole using special mini scissors, thin electric wire loops or mechanical tissue-shaving devices. Removal under direct vision rather than blind scraping is recommended so that the root is not left behind. The choice of instruments and what to keep in mind before and after the procedure are explained on the Hysteroscopy page.

As an outpatient or in the operating theatre?

• Outpatient (office-based) hysteroscopy: small, single polyps can be removed without a hospital stay or general anaesthesia, with light local anaesthesia (numbing of the area) or without any numbing, using a "see and treat" approach.
• Hysteroscopy in the operating theatre: for large or multiple polyps, or when the cervix is narrow, the procedure is done in the operating theatre under sedation (light sleep) or general anaesthesia.

Recovery

It is a minimally invasive procedure with no cut. Most women go home the same day and can return to daily life and work within 1–2 days. Recovery time can vary from person to person.

Risks

The complication (unwanted event) rate is very low (under 1%). Possible risks, which are rare, are:

• A hole in the wall of the womb (perforation),
• Bleeding,
• Infection inside the womb,
• In very few cases, adhesions inside the womb (Asherman syndrome).

Polyps in infertility and before IVF

In women who want a child and are being assessed for infertility, the rate at which a polyp is found is about 15–32%. By covering the cavity of the womb, a polyp can disturb the surface where the embryo (the earliest form of the developing baby) will attach, increase the local inflammatory response, make it harder for sperm to move forward or block the openings of the tubes.

• Before insemination (placing sperm inside the womb): in a randomised controlled study (a study in which participants are assigned to groups at random), the pregnancy rate in women whose polyp was removed before insemination was clearly higher than in those whose polyp was not removed (51% versus 28%).
• Before IVF: ESHRE and ASRM guidelines recommend removing the polyp before treatment in women planning IVF or with repeated IVF failure, in order to increase the chance of the embryo attaching.

These rates reflect the average of the groups in the studies; results can vary from person to person.

Do polyps come back?

For polyps removed completely by hysteroscopy under direct vision, together with the stalk and the base of the root, the risk of coming back is low (under 5%). The main reasons for recurrence are:

• The root of the polyp not being fully cleared and tissue being left behind,
• Continuing hormonal factors that favour polyp formation (for example oestrogen dominance or use of tamoxifen).

Fully clearing the base of the polyp lowers the risk of recurrence. In women using tamoxifen who carry a high risk, use of a levonorgestrel-releasing intrauterine device (hormonal coil) has been reported to clearly lower the risk of recurrence and of new polyps forming. Whether this option is suitable is assessed individually together with the doctor.