Atypical endometrial hyperplasia

Endometrial hyperplasia is a condition where the lining of the womb called the endometrium gets thicker. This happens because more cells have been produced. There are 2 types:

  • hyperplasia without atypia, where the cells are thicker but normal
  • atypical endometrial hyperplasia, where the cells are not normal (they are said to be atypical)

Atypical endometrial hyperplasia is the type more likely to become cancerous with time if not treated.

This information explains:

Causes of atypical endometrial hyperplasia

Atypical endometrial hyperplasia is often caused by the lining of the womb being stimulated by too much oestrogen over a long period. Oestrogen is a female sex hormone (chemical messenger). 

You can also get the condition if you have endometrial hyperplasia without atypia and this is not treated.

Your body may be more likely to make extra oestrogen if you:

  • are overweight or obese
  • have oestrogen-only hormone replacement therapy to treat the symptoms of the menopause (when you stop having periods)
  • have never been pregnant
  • have untreated polycystic ovary syndrome (PCOS)
  • have a tumour in the ovary called a granulosa cell tumour that produces oestrogen
  • take a hormone called tamoxifen to treat breast cancer
  • have diabetes
  • have a family history of ovarian, bowel or womb cancer

Symptoms of the condition

The symptoms of atypical endometrial hyperplasia usually include unusual bleeding from the womb. However, you may not have any symptoms and the condition may be discovered during a routine pelvic scan.

Common symptoms include:

  • heavy, long-lasting periods
  • bleeding in between your periods
  • unexpected or irregular bleeding if you are on hormone replacement therapy (HRT)
  • bleeding from the vagina after the menopause (when your periods have stopped)
  • an increased amount of brown vaginal discharge (fluid that comes from your vagina)

Diagnosing atypical endometrial hyperplasia

We can do the following tests to diagnose atypical endometrial hyperplasia:

Ultrasound scan

Your doctor usually arranges a vaginal scan if they think that you may have symptoms of endometrial hyperplasia. An ultrasound scan helps to:

  • measure the thickness of your womb lining
  • look for other possible causes of unusual bleeding from the womb, such as lumps (polyps) in the womb or cysts on the ovary

Endometrial biopsy

An endometrial biopsy is when we take a sample of tissue called a biopsy from the lining of your womb. This is often an outpatient procedure, which means that you do not need to stay in hospital overnight. You do not usually need an anaesthetic.

We can take the biopsy using a small plastic tube that goes through the neck of the womb. This is called an endometrial pipelle biopsy.

We can also do the procedure using a camera (hysteroscopy). This allows the doctor to take a sample called a directed biopsy from the affected area.

The sample of tissue is checked under a microscope to confirm if you have atypical endometrial hyperplasia.


This procedure allows your doctor to look inside your womb. They can then see any unusual areas and take a sample of tissue (a directed biopsy).

We can do the procedure in an outpatient clinic with or without a local anaesthetic. This is a medicine to make the area being examined numb and free from pain.

You can also have the procedure under a general anaesthetic in an operating theatre. We then give you a medicine to make you sleep during the procedure.

Treatment for the condition

If you have atypical endometrial hyperplasia that is not treated, there is a higher risk of getting cancer of the womb lining (endometrial cancer).

Your specialist doctor may recommend that you have an operation called a hysterectomy to remove the womb. We usually do this operation as robot-assisted or keyhole (laparoscopic) surgery.

If you want to get pregnant, you can talk to your specialist doctor about the options to preserve your fertility (ability to conceive children).

How to prevent atypical endometrial hyperplasia

You can lower the risk of atypical endometrial hyperplasia by:

  • treating endometrial hyperplasia without atypia with progestin (this is a form of the hormone progesterone and available as tablets or as a hormone-releasing contraceptive device called the Mirena® intrauterine system)
  • keeping to a healthy body weight for your height
  • taking combined hormone replacement therapy with oestrogen and progestin
  • taking the combined contraceptive pill or progestin tablets, or regulating your menstrual cycle with a Mirena intrauterine system if you have polycystic ovary syndrome
  • getting prompt medical advice about any unusual bleeding if you take tamoxifen for breast cancer

Support and more information

The organisations listed in this section can give you support and more information.

Macmillan Cancer Support

A charity that gives information and support to anyone affected by cancer.

Phone: 0808 808 00 00 (7 days a week, 8am to 8pm)
Website: www.macmillan.org.uk

Cancer Research UK

A charity that gives information on all types of cancer and treatment options.

Phone: 0300 123 1022 (Monday to Friday, 8am to 8pm, Saturday and Sunday, 9am to 5pm)
Website: www.cancerresearch.org

Endometriosis UK

A charity that gives support and information for people affected by endometriosis. 

Phone: 0808 808 2227
Website: www.endometriosis-uk.org

Resource number: 5475/VER1
Last reviewed: March 2024
Next review due: March 2027

A list of sources is available on request.

Trusted Information Creator. Patient Information Forum

Contact us

If you have any questions or concerns about atypical endometrial hyperplasia, please contact:

Pharmacy medicines helpline

If you have any questions or concerns about your medicines, please speak to the staff caring for you. 

You can also contact our pharmacy medicines helpline.

Phone: 020 7188 8748, Monday to Friday, 9am to 5pm

Email: [email protected]

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