Endometrial Polyps: What They Are, Why They Matter, and When to Act

Endometrial polyps are soft, tissue-like growths that form in the lining of the uterus. Many women have them without ever knowing — they’re often harmless and cause no symptoms. But in some cases, they can lead to irregular bleeding, fertility issues, or even carry a small risk of cancer. If you’re experiencing any unusual symptoms, understanding what polyps are and how they behave can help you make informed choices about your health.

What Are Endometrial Polyps?

These polyps are made up of glands, connective tissue, and blood vessels — all components of the endometrium, which is the lining of the uterus. They can range in size from a few millimetres to a few centimetres and may occur alone or in clusters (Yuksel et al., 2021). Most are benign, but some can develop atypical cells or, more rarely, become cancerous, especially in postmenopausal women (Cetin et al., 2024; Meng et al., 2023).

Why Do They Develop?

There’s no single reason why endometrial polyps form, but several contributing factors are well documented:

High oestrogen levels – Oestrogen stimulates the uterine lining to grow. If there’s too much oestrogen and not enough progesterone to balance it, the tissue can overgrow and form polyps (Meng et al., 2023).
Ageing and hormone shifts – Most polyps appear in women over 40. Around this time, hormone levels fluctuate more often, and the lining of the uterus may respond irregularly, increasing the chance of polyps developing (Yuksel et al., 2021).
Tamoxifen – A drug used in breast cancer treatment, tamoxifen mimics oestrogen in the uterus and can trigger polyp formation (Romero et al., 2021).
PCOS (Polycystic Ovary Syndrome) – Women with PCOS may go long periods without ovulating. This means the endometrium is exposed to oestrogen for longer without progesterone to reset the cycle, creating a favourable environment for polyps (Lu et al., 2023).
Metabolic issues – Conditions like insulin resistance and chronic inflammation can interfere with hormone balance and make the uterine lining more reactive and prone to abnormal growth (Cetin et al., 2024).

How Do They Show Up?

Many polyps cause no symptoms at all and are found by chance during a scan or investigation. But when they do cause problems, common signs include:

Spotting between periods or after sex – Polyps have their own blood supply and can bleed easily, even outside your normal cycle.
Heavier or longer periods – If a polyp increases the surface area inside the uterus, more lining builds up and more is shed, leading to heavier flow (Yuksel et al., 2021).
Pain during sex – Especially if the polyp is near the cervix and gets disturbed.
Trouble getting pregnant – Polyps can affect fertility by disrupting the space where an embryo would implant or by causing inflammation in the uterus (Jee & Jeong, 2021).

Can They Affect Fertility?

Yes. Even small polyps can reduce the likelihood of implantation by altering the uterine environment. They may physically block sperm or embryo movement, create inflammation, or interfere with the hormonal signals needed for implantation. Fortunately, many women conceive naturally after having them removed (Jee & Jeong, 2021).

How Are They Diagnosed?

Polyps can be tricky to spot, especially smaller ones. Here’s how they’re usually found:

Transvaginal ultrasound – A standard scan that gives a general view but might miss smaller or flatter polyps.
Saline infusion sonography (SIS) – A small amount of fluid is inserted into the uterus during ultrasound, helping the doctor see the shape of the cavity more clearly.
Colour Doppler imaging – This shows blood flow and can help spot vascular features typical of polyps.
Hysteroscopy – A thin camera is passed into the uterus, giving a direct view and allowing polyps to be removed during the same procedure (Zhang et al., 2022; Yuksel et al., 2021).

Polyps vs Fibroids — What’s the Difference?

It’s easy to confuse these two. Both are growths inside the uterus and can cause similar symptoms like heavy bleeding. But they’re quite different in nature.

Polyps come from the endometrial lining and are usually small, soft, and made of gland-like tissue.
Fibroids grow from the muscle wall of the uterus. They’re usually firmer and can be located deep in the wall, inside the cavity, or on the outer surface.

Some fibroids, especially the ones that grow into the cavity (submucosal), can look a lot like polyps on ultrasound. This is where SIS or hysteroscopy helps make a clear distinction (Zhang et al., 2022; Kliman, n.d.; USA Fibroid Centers, n.d.).

When Should You Be Concerned?

Most polyps are harmless. But there are times when they need more attention:

They’re large
You have postmenopausal bleeding
You’ve had abnormal bleeding for a while
You have other uterine conditions like fibroids or hyperplasia
Blood tests show raised inflammatory or glucose levels (Cetin et al., 2024)

A study in postmenopausal women found abnormal or cancerous changes in 1 in 5 removed polyps (Meng et al., 2023), so it’s always worth checking anything unusual.

How Are They Treated?

Treatment depends on your age, symptoms, and overall risk. Options include:

Watch and wait – If you’re premenopausal and the polyp is small with no symptoms, your doctor might suggest monitoring (Yuksel et al., 2021).
Hysteroscopic polypectomy – A straightforward, minimally invasive procedure that allows the polyp to be removed during a short hospital visit (Zhang et al., 2022).
Hormonal therapy – In some cases, short-term hormone treatment may help manage symptoms or reduce the chance of recurrence (Nazari et al., 2024).

The Bottom Line

Most endometrial polyps don’t cause problems — but when they do, they’re worth paying attention to. If you’ve noticed unusual bleeding, difficulty conceiving, or any changes in your cycle, speak to a healthcare professional. Diagnosis is simple, treatment is usually minor, and peace of mind is worth it.

References

Romero, S.A.D., Young, K., Hickey, M., & Su, H.I. (2021). Levonorgestrel intrauterine system for endometrial protection in women with breast cancer on adjuvant tamoxifen (Review). Cochrane Database of Systematic Reviews, (2). doi:10.1002/14651858.CD007170.pub3
Yuksel, S., Tuna, G., Goksever Celik, H., & Salman, S. (2021). Endometrial polyps: Is the prediction of spontaneous regression possible? Journal of Obstetrics and Gynaecology Research.
Cetin, F., Kayar, I., Birge, O., & Goc, G. (2024). Malignancy risk factors based on endometrial polyp. Medicina, 60(2), 275. doi:10.3390/medicina60020275
Meng, Q., Ge, N., Fan, Y., & Li, L. (2023). Analysis of ultrasonic imaging changes and factors related to malignant transformation in postmenopausal patients with endometrial polyps. Journal of Obstetrics and Gynaecology Research.
Lu, L., Luo, J., Deng, J., Huang, C., & Li, C. (2023). Polycystic ovary syndrome is associated with a higher risk of premalignant and malignant endometrial polyps in premenopausal women: a retrospective study in a tertiary teaching hospital. Gynecological Endocrinology, 39(1), 1–5.
Jee, B.C., & Jeong, H.G. (2021). Management of endometrial polyps in infertile women: A mini-review. Clinical and Experimental Reproductive Medicine, 48(1), 1–6.
Zhang, Y., Bai, X., Liu, H., Wang, X., & Lang, J. (2022). Role of surgical vaginoscopy through no-touch hysteroscope in the treatment of female reproductive polyps. Archives of Gynecology and Obstetrics.
Sidera, A., Matalliotakis, M., Tsakiridis, I., et al. (2025). Coexistence of Gynecological Pathologies in Women With Cervical and Endometrial Polyps. Cureus, 17(1), e77015. doi:10.7759/cureus.77015
Nazari, L., Vahdat, M., Rokhgireh, S., et al. (2024). HPV infection and endometrial polyps: insights from a case-control study. BMC Women’s Health, 24:598. doi:10.1186/s12905-024-03412-5
Kliman, L. (n.d.). Fibroids vs Polyps: Understanding the Difference. Retrieved from https://drlenkliman.com.au/articles/fibroids-vs-polyps-understanding-the-difference/
USA Fibroid Centers. (n.d.). What Is the Difference Between Uterine Polyps vs. Fibroids? Retrieved from https://fibroids.com/blog/health-information/what-is-the-difference-between-uterine-polyps-vs-fibroids/