Endometrial hyperplasia is a thickening of the inner lining of the womb (uterus). It usually causes abnormal vaginal bleeding. It may return to normal without any treatment in some cases. In others, hormone treatment or an operation may be needed. In some women it may progress to a cancer of the lining of the womb. Treatment is usually successful and prevents cancer from developing.
What is endometrial hyperplasia?
Endometrial hyperplasia is a thickening of the lining of the womb (uterus). The endometrium is the inner lining of the womb. In women who have not reached their menopause, this lining is shed each month during a menstrual period. Hyperplasia means excessive growth. In endometrial hyperplasia, the cells that make up the endometrium multiply excessively, so that it becomes thicker.
There are two types of endometrial hyperplasia:
- Hyperplasia without atypia. In this type, the lining of the womb is thicker, as more cells have been produced. The cells are all normal, however, and are very unlikely to ever change to cancer. Over time, the overgrowth of cells may stop on its own, or may need treatment to do so.
- Atypical hyperplasia. In this type, the cells are not normal (they are said to be atypical). This type of hyperplasia is more likely to become cancerous over time if not treated.
Who develops endometrial hyperplasia?
Endometrial hyperplasia is more common in women after their menopause, but may occur in younger women before menopause. Endometrial hyperplasia is caused by an excess of the hormone oestrogen, which is not balanced by the progesterone hormone. Certain conditions make you more likely to have this imbalance, and endometrial hyperplasia is more common if this is the case. However, any woman can develop endometrial hyperplasia. It is more common if:
- You are overweight.
- You take certain types of hormone replacement therapy (HRT).
- You have not had children.
- You have polycystic ovary syndrome (PCOS).
- You have an unusual type of tumour of the ovary, such as a granulosa cell tumour.
- You take a medicine called tamoxifen (for breast cancer).
- You have diabetes.
What are the symptoms of endometrial hyperplasia?
Usually endometrial hyperplasia causes vaginal bleeding which is different to your usual pattern. Some women may have bleeding in between their periods, when it is not expected. In other women, periods may become heavier or more irregular. If you have already stopped your periods and are in your menopause, you may experience unexpected bleeding. If you take HRT, you may get bleeding at a time when you do not usually have a bleed. Some women may have a vaginal discharge. In some women there may be no symptoms, and the hyperplasia may be picked up whilst having tests for other reasons.
What tests are needed?
An ultrasound scan
An ultrasound scan is usually arranged. This can check for other causes of bleeding, such as lumps (polyps) in the womb (uterus), or cysts on the ovaries. The scan can also measure the thickness of the lining of the womb.
In women who have had their menopause, this is particularly helpful. After your menopause, the lining of the womb is normally very thin (under 3-4 mm). So if the scan picks up a thicker lining, your doctor will arrange further tests. Whereas, if the lining is less than 3 mm, it is unlikely that you have endometrial hyperplasia.
If you are still having periods, it is harder to determine if the lining of the womb is normal. This is because the thickness varies during your monthly cycle. If it is less than 7 mm when measured, it is usually reassuring. However, ultrasound is more useful for making sure there are no other abnormalities in this age group.
An endometrial biopsy
A biopsy is a sample of tissue taken to be analysed under the microscope. An endometrial biopsy is usually done as an outpatient. No anaesthetic is usually required. A small tube is passed into the womb through the vagina. A sample of the endometrium is sucked out and sent to the laboratory for analysis. This procedure may be uncomfortable and there may be some light bleeding and mild discomfort for a few days afterwards.
A hysteroscopy is a test used to allow the doctor to look inside the womb. This is done using a narrow tube-like instrument called a hysteroscope. It is carefully passed through the vagina and neck of the womb (cervix) and into your uterus. The hysteroscope has a video camera inside which sends pictures to a computer screen. This allows your doctor to see the inside of the womb and to take biopsies from specific chosen areas of thickening. A hysteroscopy can be performed in an outpatient clinic with local anaesthetic, or it can be done in hospital with a general anaesthetic.
What is the treatment for endometrial hyperplasia?
Treatment for endometrial hyperplasia depends on which type you have. This will have been shown on the endometrial biopsy sample.
Treatment for endometrial hyperplasia without atypia
This type of hyperplasia very rarely turns into cancer, so treatment is not always needed. One option is to do nothing and repeat the biopsy in a few months to see if it has settled back to normal on its own. In many cases this can happen. However, it is more likely to return to normal (regress) if you have treatment. The best treatment for this type of endometrial hyperplasia is to have the intrauterine system (IUS) put in. This is better known as a contraceptive device (a type of coil). It releases a progestogen hormone which thins the lining of the womb (uterus). This stays in for at least six months, but for up to five years. It has a good success rate in treating endometrial hyperplasia. An alternative is to have progestogen tablets each day for six months. These are not quite as effective as the IUS and they may have more side-effects.
Occasionally an operation to remove the womb (a hysterectomy) is needed. This operation is not normally needed for this type of endometrial hyperplasia. However, it may be considered if:
- The hormone treatments are not working after 6-12 months.
- The condition comes back after treatment.
- You go on to develop atypical hyperplasia.
- You prefer to have an operation than to take regular medication or have an IUS. However, a hysterectomy is quite a big operation to recover from, so you would need to discuss the pros and cons with your specialist.
Being very overweight puts you at more risk of endometrial hyperplasia. So, if you are overweight, it seems likely that losing weight will make it less likely that the hyperplasia will return in future after treatment.
Treatment for atypical endometrial hyperplasia
If you have atypical endometrial hyperplasia, your specialist will probably recommend you have a hysterectomy. This is an operation to remove the womb. This is to prevent you developing a cancer of the lining of the womb. If you are in the menopause, you will be offered removal of your ovaries and Fallopian tubes as well; this is called a hysterectomy and salpingo-oophorectomy.
If you want to be able to get pregnant and you do not want a hysterectomy, you can discuss the options with your specialist. You may be able to have hormone treatment for six months and if a repeat biopsy shows it has worked, you may be able to delay a hysterectomy until after you have completed your family. However, you will still be advised to have a hysterectomy at some point, as there is a high chance the endometrial hyperplasia will return, and a risk that it may change to cancer. You may be referred to a fertility specialist for further advice.
What is the outcome (prognosis) for endometrial hyperplasia?
In most cases, hyperplasia without atypia is successfully treated with hormones. Over the 20 years after diagnosis, fewer than 5 out of every 100 women who have it develop cancer of the womb (uterus).
The hyperplasia can return after treatment. It appears more likely to return if you are overweight with a body mass index (BMI) of more than 35.
Atypical hyperplasia can turn into cancer of the womb. 20 years after diagnosis, around 28 out of every 100 women diagnosed with atypical hyperplasia will develop cancer of the womb. However, hysterectomy is a complete cure if carried out before the cancer develops. After a hysterectomy for endometrial hyperplasia, the condition cannot return, as there is no endometrium left to grow. Because of the abnormal bleeding it causes, endometrial hyperplasia is usually diagnosed and treated quickly before it can cause complications.
Further reading and references
Management of Endometrial Hyperplasia; RCOG/BSGE Joint Guideline (2016)
Abu Hashim H, Ghayaty E, El Rakhawy M; Levonorgestrel-releasing intrauterine system vs oral progestins for non-atypical endometrial hyperplasia: a systematic review and metaanalysis of randomized trials. Am J Obstet Gynecol. 2015 Oct213(4):469-78. doi: 10.1016/j.ajog.2015.03.037. Epub 2015 Mar 19.
Luo L, Luo B, Zheng Y, et al; Levonorgestrel-releasing intrauterine system for atypical endometrial hyperplasia. Cochrane Database Syst Rev. 2013 Jun 56:CD009458. doi: 10.1002/14651858.CD009458.pub2.
Wise MR, Jordan V, Lagas A, et al; Obesity and endometrial hyperplasia and cancer in premenopausal women: A systematic review. Am J Obstet Gynecol. 2016 Jun214(6):689.e1-689.e17. doi: 10.1016/j.ajog.2016.01.175. Epub 2016 Jan 30.
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