Uterine polyps

This page was reviewed under our medical and editorial policy by

Barbara Buttin, MD, Gynecologic Oncologist

This page was updated on March 8, 2024.

Uterine polyps, often referred to as endometrial polyps, are abnormal growths that develop on the inner lining of the uterus, or endometrium. Most of these polyps are benign, meaning they’re not cancerous. However, in rare instances, they may become precancerous or cancerous.

To help patients understand uterine polyps and their potential link to uterine cancer, this article will explore:

What are uterine polyps?

Uterine polyps are excess growths that develop on the endometrium, the innermost layer of the uterus. They vary in size and may be as small as a sesame seed or as large as grape. They may appear singly or in clusters and are usually connected to the endometrium by a thin stalk or broader base.

While uterine polyps are common among women in their 40s and 50s, they may affect women of any age. Polyps are rare in women younger than 20. Among women undergoing hysterectomy or localized endometrial biopsy, the prevalence of polyps is estimated to be between 10 percent and 24 percent, research shows.

What causes uterine polyps?

The exact cause of uterine polyps is unclear, though some have been linked to hormonal factors. Uterine polyps are estrogen-sensitive, meaning they grow in response to circulating estrogen.

During the menstrual cycle, estrogen levels rise and fall, causing the endometrial lining to thicken and then shed. Scientists believe an overgrowth of this lining may lead to the formation of uterine polyps.

An increased risk for developing uterine polyps may also be caused by other factors, such as obesity, high blood pressure (hypertension) and taking tamoxifen, a drug therapy for breast cancer.

Uterine polyps vs. fibroids

Uterine polyps and fibroids are different types of abnormal growths in the uterus, but they have distinct characteristics.

While uterine polyps may result from an overgrowth of the endometrial lining, uterine fibroids are non-cancerous tumors that originate from the muscle layer of the uterus. Fibroids, which are made up of smooth muscle cells and connective fibrous tissue, can vary in size, location or number.

Symptoms of these two conditions may be similar, but they are differentiated by key distinctions. For instance, fibroids often cause heavy menstrual bleeding, abdominal pain or pressure, and frequent urination, while polyps typically cause irregular menstrual bleeding or spotting.

How often are uterine polyps cancerous?

While most uterine polyps are benign, a small percentage may be precancerous or cancerous. A comprehensive mega analysis published in the European Journal of Obstetrics & Gynecology and Reproductive Biology found that just 2.73 percent of polyps in women are cancerous.

Although this percentage is relatively low, it’s important to note that any uterine polyp should be evaluated by a health care provider to rule out the possibility of cancer.

Uterine polyp symptoms

Symptoms of uterine polyps may vary. Many women with uterine polyps don’t experience any symptoms. When symptoms do occur, they may include:

  • Irregular or heavy menstrual bleeding
  • Vaginal bleeding between menstrual periods
  • Post-menopausal bleeding
  • Infertility

How are uterine polyps diagnosed?

If uterine polyps are suspected, the patient’s health care provider will likely start by taking a thorough medical history and asking about symptoms. This oral history is typically followed by a gynecological exam, including a pelvic exam and possibly a Pap smear.

Further diagnostic tests may be necessary to confirm the presence of uterine polyps, including those listed below.

Transvaginal ultrasound: For this procedure, a slim, handheld device (an ultrasound transducer) is inserted into the vagina. This device emits sound waves that create an image of the inside of the uterus, revealing any irregularities, such as polyps.

Sonohysterography: Following an initial transvaginal ultrasound, a sterile fluid may be introduced into the uterus via a thin tube or catheter for this diagnostic test. This fluid expands the uterus, providing a clearer image of growths in the uterine cavity.

Hysteroscopy: This procedure involves inserting a long, thin tube with a lighted telescope (hysteroscope) into the uterus through the vagina and cervix to check for abnormalities. The hysteroscope provides a direct view of the inside of the uterus.

Endometrial biopsy: In some cases, a soft plastic instrument is used to collect a tissue sample from the inner walls of the uterus. The sample that is then tested in a laboratory to determine the presence of abnormal cells.

Curettage: A long, metal instrument, known as a curette, may be used to scrape tissue or polyps from the inner walls of the uterus. The removed tissue or polyps are then sent to a laboratory for testing to check for the presence of cancer cells.

Uterine polyp treatment

The treatment of uterine polyps depends on several factors, including the patient's symptoms, age and other risk factors for developing uterine cancer. If a pre-menopausal woman has asymptomatic uterine polyps, her doctor may choose to monitor the polyps without providing immediate treatment, since they often resolve on their own.

However, in postmenopausal women, or in patients whose polyps are causing symptoms, treatment may be necessary. Therapeutic approaches for uterine polyps may include hormone therapy or minimally invasive, surgical removal.

Hormone therapy: Medications used to treat uterine polyps are typically designed to regulate hormones. These include progestins or gonadotropin-releasing hormone agonists, which are used to alleviate symptoms. However, these are usually a short-term solution, since symptoms typically recur once the medication has been discontinued.

Polypectomy: A polypectomy, or hysteroscopic resection, is often performed in an outpatient setting. This is a minimally invasive surgical procedure performed to remove polyps that have formed in the lining of the uterus or cervix.

During the procedure, the surgeon inserts a small camera known as a hysteroscope into the uterus to see the polyps without the need for incisions. Once the polyps are identified, the surgeon then uses a wire loop or similar tool attached to the hysteroscope to remove the polyps.

The entire procedure usually takes 30 minutes to an hour, depending on the size and number of polyps removed. After the surgery, the polyps are typically sent to a lab to rule out cancerous growths.

Patients may experience some mild cramping and spotting after a polypectomy, which should resolve within a few days. They are typically advised to rest and avoid strenuous activities for a few days following uterine polyp removal. Pain medication may be prescribed to manage any discomfort.

What happens if a uterine polyp is cancerous?

Cancerous uterine polyps are rare. A pathologist will analyze the removed polyps, and if they’re cancerous, they’ll determine whether all the cancer was removed. If remaining cancer is detected, further treatment, staging and evaluation may be required.

How to prevent uterine polyps

Uterine polyps cannot be prevented. However, regular gynecological checkups may help detect these growths early, when they can be more easily managed, and even before they cause complications or unpleasant symptoms. That’s why it’s critical for patients to remain vigilant and promptly report abnormal bleeding or other symptoms to their gynecologist.

Regular screenings and early intervention have been known to significantly improve outcomes for women with uterine polyps.

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Show references
  • National Library of Medicine (2022, Sep. 30). Endometrial Polyps https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9804076/
  • National Library of Medicine (2019, Apr. 15). The risk of malignancy in uterine polyps: A systematic review and meta-analysis https://pubmed.ncbi.nlm.nih.gov/31009859/
  • Walters Kluwer, UptoDate® (2023, May. 01). Endometrial polyps. https://www.uptodate.com/contents/endometrial-polyps
  • National Library of Medicine (2019, May 2). Endometrial polyps: Pathogenesis, sequelae and treatment - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6501471/
  • National Library of Medicine (2023, April 25). Endometrial Polyp https://www.ncbi.nlm.nih.gov/books/NBK557824/
  • Human Pathology (2021, Jul 7). Minimal uterine serous carcinoma and endometrial polyp: a close clinicopathological relationship https://www.sciencedirect.com/science/article/abs/pii/S0046817721001520
  • Best Practice & Research Clinical Obstetrics & Gynaecology (2015, Jun 25). Hysteroscopy and treatment of uterine polyps https://www.sciencedirect.com/science/article/abs/pii/S152169341500108X
  • Obstetrics & Gynecology (2002, Jun 27). Natural history of uterine polyps and leiomyomata https://www.sciencedirect.com/science/article/abs/pii/S0029784402020070