Endometrial hyperplasia

What is endometrial hyperplasia?

Endometrial hyperplasia is a thickening of the endometrium which is the womb (uterus) lining. It can cause 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. 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.

Endometrial hyperplasia symptoms

Usually endometrial hyperplasia causes vaginal bleeding which is different to the 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.

Women whose periods have stopped as they are in the menopause may experience unexpected bleeding (post-menopausal bleeding). Women taking sequential HRT (which usually causes regular bleeds) may get vaginal bleeding at an unexpected time. Some women may have an unusual vaginal discharge. In some women there may be no symptoms, and the hyperplasia may be picked up whilst having tests for other reasons.

What causes endometrial hyperplasia?

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 hormonal imbalance, and endometrial hyperplasia is more common if this is the case. However, any woman can develop endometrial hyperplasia. It is more common if the woman:

• Is overweight.

• Is using the oestrogen element of hormone replacement therapy (HRT) without sufficient progesterone.

• Has not had children.

• Has polycystic ovary syndrome (PCOS).

• Has a rare type of tumour of the ovary, such as a granulosa cell tumour.

• Takes a medicine called tamoxifen (for breast cancer) (but not other types of breast cancer medication such as letrozole, anastrozole or exemestane)

• Has diabetes.

How is endometrial hyperplasia diagnosed?

An ultrasound scan

An ultrasound scan is usually arranged if a doctor suspects endometrial hyperplasia symptoms. This can check for other causes of bleeding, such as polyps (benign fleshy lumps) in the womb (uterus), or cysts on the ovaries. The scan can also measure the thickness of the womb lining.

Following the menopause, the lining of the womb is normally very thin. So if the scan picks up a thicker womb lining, further tests will usually be arranged following a referral to a gynaecologist. If the lining is less than 5mm then referral is not usually necessary.

In women who are still having periods, it is harder to determine if the lining of the womb is normal. This is because the thickness varies during the monthly cycle. If it is less than 7 mm when measured, it is usually reassuring; if it is thicker then a repeat ultrasound is often helpful. However, ultrasound is more useful for making sure there are no other abnormalities in this age group.

An endometrial biopsy

An endometrial biopsy involves taking cells from the lining of the womb. This is usually done to check for causes of abnormal vaginal bleeding. Endometrial biopsy is also sometimes carried out in women having treatment for infertility.

An endometrial biopsy is a quick procedure that doesn't require a general anaesthetic. It is taken in a similar way to a smear test, using a plastic speculum to widen the vagina. A local anaesthetic may be used (as a gel or as an injection into the cervix) before a thin tube is passed into the womb to take the sample.

Our separate leaflet called Endometrial biopsy gives more information.

A hysteroscopy

A hysteroscopy allows the doctor to see inside the womb using a thin tube-like telescope. This procedure can be carried out using a local or general anaesthetic. A hysteroscopy allows the doctor to check for any womb abnormalities. They can also take biopsies or sometimes remove polyps from the womb.

You can find more details from our separate leaflet called Hysteroscopy.

Endometrial hyperplasia treatment

Treatment options for endometrial hyperplasia depends on the type. This will have been shown on the endometrial biopsy sample.

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) with treatment. The best treatment for this type of endometrial hyperplasia is to insert a intrauterine system (IUS). This is better known as a contraceptive device (a type of coil). It releases a progestogen hormone which thins the lining of the uterus (womb). This stays in for at least six months, but for up to eight 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 may have more side-effects.

Endometrial ablation is a newer technique for removing the endometrium (womb lining) and is often used for abnormal bleeding. It is not recommended as a treatment for endometrial ablation.

Hysterectomy

A hysterectomy (removal of the womb) is not normally needed for this type of endometrial hyperplasia although it was commonly performed for this reason in the past. However, it may be considered if:

• The hormone treatments are not working after 6-12 months.

• The condition comes back after treatment.

• Atypical hyperplasia later develops.

• A woman prefers to have an operation than to take regular medication or have an IUS. However, a hysterectomy is a significant operation to recover from so this would need careful discussion with a gynaecologist.

Being very overweight increases the risk of endometrial hyperplasia. It therefore seems likely that losing weight will reduce the risks that the hyperplasia will return in future after treatment.

Atypical endometrial hyperplasia

Studies have shown that atypical endometrial hyperplasia will develop into endometrial cancer in more than 8 in 100 women. Therefore, women with atypical endometrial hyperplasia will usually be advised to have a hysterectomy. This is an operation to remove the womb. This is to prevent a cancer of the lining of the womb from developing.

Women in the menopause will usually be offered removal of the ovaries and Fallopian tubes as well; this is called a hysterectomy and salpingo-oophorectomy.

Women with atypical endometrial hyperplasia who want to retain the option of getting pregnant have some other options. They may be able to have hormone treatment for six months and, if a repeat biopsy shows it has worked, they may be able to delay a hysterectomy until after they have completed their family. However, they will usually be advised to have a hysterectomy at some point, as there is a high chance the endometrial hyperplasia will return, and a fairly high risk that it may change to cancer.

How can I prevent endometrial hyperplasia?

Endometrial hyperplasia cannot be completely prevented, but the risk can be lowered by:

• Maintaining a healthy weight.

• Taking regular progesterone, if taking oestrogen for the menopause or any other condition.

• Taking a birth control pill or another medicine to regulate the menstrual cycle.

• Not smoking.

What is the outcome (prognosis) of 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 with a body mass index (BMI) of more than 35.

Atypical hyperplasia can turn into 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. In women who have had a hysterectomy for endometrial hyperplasia but who also have a diagnosis of endometriosis, there is a theoretical risk of cancer developing in the endometrial deposits elsewhere in the abdomen or pelvis. However this is very rare indeed and there have been almost no cases reported.

Because of the abnormal bleeding it causes, endometrial hyperplasia is usually diagnosed and treated quickly before it can cause complications.