Endometrial Polyps (Uterine Polyps)

What endometrial polyps are

The endometrium thickens and sheds every month in response to estrogen and progesterone. A polyp forms when one area of the lining overgrows, building a finger-like or rounded mass with its own blood vessels. Polyps can be:

• pedunculated: attached by a thin stalk, sometimes long enough to poke through the cervix
• sessile: attached by a broad, flat base
• single or multiple, and usually under 2 cm

They are found in roughly 10% or more of women overall and in a larger share of those investigated for abnormal bleeding. They are distinct from uterine fibroids, which grow from the muscle wall, and from cervical polyps, which grow in the cervical canal.

Symptoms

• Bleeding or spotting between periods (intermenstrual bleeding), the most typical sign
• Heavy or prolonged periods (heavy menstrual bleeding)
• Irregular periods with no predictable pattern
• Bleeding after sex
• Bleeding after menopause
• Infertility or recurrent miscarriage, in some cases

Polyps rarely cause pain. Cramping can occur if a large stalked polyp is pushed toward the cervix. Many polyps are found by chance on an ultrasound done for another reason.

Causes and risk factors

Estrogen drives the lining to grow, so most risk factors involve more estrogen or less opposing progesterone:

• age 40 to 60, with a peak around perimenopause
• obesity (fat tissue makes estrogen)
• tamoxifen for breast cancer: up to a third of users develop polyps
• estrogen-only hormone therapy
• high blood pressure
• Lynch syndrome and some other inherited conditions

Are endometrial polyps cancerous?

Most are benign. About 1 to 5% contain atypical endometrial hyperplasia (a precancerous change) or endometrial cancer. The risk is higher with:

This is why polyps found after menopause or causing bleeding are usually removed and examined.

Diagnosis

1. Transvaginal ultrasound: a probe in the vagina shows the lining. A polyp appears as a focal thickening or a mass with a feeding vessel on Doppler.
2. Saline infusion sonohysterography: sterile saline is gently run into the uterus during the ultrasound, outlining any polyp clearly.
3. Hysteroscopy: a thin camera passed through the cervix shows the cavity directly and allows the polyp to be removed in the same session. This is the most accurate test.
4. Endometrial biopsy: a thin tube samples the lining in the office. It can miss polyps but helps rule out cancer.

Treatment

Watchful waiting

Small polyps (under about 1 cm) that cause no symptoms in premenopausal women can be monitored. A proportion shrink or disappear on their own within a year.

Hysteroscopic polypectomy

Removal is recommended for polyps that cause bleeding, are found after menopause, occur with tamoxifen, are linked with infertility, or are large. The surgeon passes a hysteroscope through the cervix and cuts the polyp at its base using small scissors, a loop or a tissue-removal device.

• usually an outpatient procedure, sometimes done in the office with local anesthetic
• takes 10 to 30 minutes
• most people return to normal activity the next day
• light bleeding and cramping for a few days are normal
• serious complications such as perforation of the uterus are uncommon

The tissue is always sent to a lab. Blind dilation and curettage (D&C) without a camera often misses polyps and is no longer preferred.

Medicines

Hormonal medicines such as progestins or a levonorgestrel IUD can reduce bleeding but do not reliably remove polyps. A levonorgestrel IUD may lower the risk of polyps in women taking tamoxifen.

Hysterectomy

Removal of the uterus is reserved for cancer, precancer, or repeated polyps with other problems in women who do not want future pregnancy.

Polyps and fertility

Polyps may interfere with embryo implantation, block the tubal openings or cause inflammation in the lining. Removing polyps before IUI has been shown in a clinical trial to improve pregnancy rates, and many fertility specialists remove them before IVF. If you have infertility and a polyp is seen, discuss removal before treatment.

Outlook and recurrence

Removal usually stops the abnormal bleeding. Polyps can come back, especially with ongoing risk factors such as obesity or tamoxifen. New bleeding after removal should be reported and investigated again.

Frequently asked questions

What are the symptoms of endometrial polyps?

The most common are spotting between periods, heavy or irregular periods, bleeding after sex and bleeding after menopause. Some people have difficulty getting pregnant. Many polyps cause no symptoms and are found only on an ultrasound done for another reason.

Are endometrial polyps cancerous?

Most are not. About 1 to 5% contain precancerous or cancerous cells. The risk is highest after menopause, when the polyp causes bleeding, in larger polyps and in women taking tamoxifen. Removing the polyp and testing it in a lab gives a definite answer.

Do uterine polyps need to be removed?

Not always. Small polyps without symptoms in women who have not reached menopause can be watched, and some go away on their own. Removal is advised for polyps that cause bleeding, appear after menopause, affect fertility, or are large.

Can endometrial polyps go away on their own?

Yes, some small polyps regress, most often in premenopausal women, within months to a year. Larger polyps and those after menopause are less likely to disappear and are usually removed.

How long does recovery from polyp removal take?

Most people go home the same day and return to work in 1 to 2 days. Light bleeding or brown discharge and mild cramps can last a few days to 2 weeks. Avoid tampons, sex and swimming for about a week, or as your doctor advises.

Can endometrial polyps cause infertility?

They can contribute. Polyps may make it harder for an embryo to implant, especially if large, multiple or near the tubal openings. Removing them has improved pregnancy rates in some studies, so fertility specialists often remove polyps before IUI or IVF.