Risk Factors for Endometrial Hyperplasia

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Endometrial hyperplasia is an abnormality of the lining of your uterus or endometrium. Caused by a hormonal imbalance, it may lead to abnormal uterine bleeding.

With your menstrual cycle, the endometrium thickens and sheds each month as part of your monthly menstrual flow. Your ovaries normally produce estrogen and progesterone in response to stimulating hormones from the brain.

This balance of estrogen and progesterone makes your period come regularly, roughly every 28 days. If these hormones become imbalanced, the endometrium can get irregularly thick. This abnormal change is called endometrial hyperplasia.

This article discusses the symptoms, causes, and risk factors of endometrial hyperplasia. It also covers how it's diagnosed and treated.

Nurse holding a model of a uterus
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Endometrial Hyperplasia Symptoms

Endometrial hyperplasia can cause abnormal uterine bleeding. This can include:

  • Heavier than normal menstrual bleeding
  • Bleeding in between your periods
  • Post-menopausal bleeding

Abnormal uterine bleeding is the most common sign that you may have endometrial hyperplasia. See your healthcare provider to discuss these changes in your bleeding. Your healthcare provider can then decide if further testing and evaluation are necessary.


Endometrial hyperplasia is caused by a hormonal imbalance, specifically too much estrogen compared to progesterone. Estrogen is the hormone that is responsible for causing the normal thickening of the endometrium during the first half of your menstrual cycle.

When balanced with the right amount of progesterone, your endometrium builds up, but then thins out. When there is too much estrogen, the lining is overstimulated and continues to thicken. Over time, that thickened lining begins to develop abnormal changes.


Estrogen causes your endometrium to thicken during your menstrual cycle. If you have too much estrogen compared to progesterone, the endometrium gets too thick and may develop abnormal changes.

Risk Factors

Conditions that cause excess estrogen that can lead to endometrial hyperplasia include:


Fat tissue converts other hormones to estrogen. This results in extra estrogen that stimulates the lining of the uterus in addition to the normal estrogen produced by your ovaries. If your BMI is over 35, you have a significantly increased risk of developing endometrial hyperplasia.


Anovulation happens when you don't ovulate, meaning an egg doesn't release from your ovaries. If you don't ovulate, your ovary won't increase its production of progesterone. This increase in progesterone is necessary for the lining of your uterus to shed. In other words, you won’t get your period.

In some types of anovulatory cycles, this leads to too much estrogen compared to progesterone. This unbalanced estrogen results in abnormal thickening of the endometrium. Eventually, you will have some type of abnormal uterine bleeding.

This may cause irregular and heavy periods or bleeding between your periods. Common causes of this type of hormonal imbalance include:


Obesity can lead to increased estrogen and a higher risk of endometrial hyperplasia. Some conditions, such as perimenopause and PCOS, can also cause hormonal imbalances that lead to thickening of the endometrium.

Taking Hormones

Hormones that are taken as medications or hormone therapy can increase your estrogen levels relative to your progesterone. One example is estrogen replacement. If you're taking estrogen replacement and still have a uterus, you need to take some form of a progestin (progesterone). This helps prevent your endometrium from being overstimulated when taking estrogen.

Another hormonal medication that can cause abnormal thickening of the endometrium is tamoxifen. Tamoxifen is a drug that is called a selective estrogen receptor modulator or SERM. SERMs are drugs that affect the estrogen-sensitive parts of your body in different ways.

Tamoxifen is often used in the treatment of hormone-sensitive breast cancers. That's because it opposes the effects of estrogen in the breast tissue. However, tamoxifen stimulates the estrogen receptors in the lining of the uterus. It acts like an estrogen and can cause endometrial hyperplasia.

See your healthcare provider if you are using hormone replacement therapy or tamoxifen and develop abnormal uterine bleeding.

Estrogen-Producing Ovarian Tumors

Hormone-producing tumors are not a common cause of endometrial hyperplasia. However, there are certain (usually benign) ovarian tumors that produce excess estrogen. 


When you see your healthcare provider for abnormal uterine bleeding, you will likely undergo a biopsy of your uterus lining. Your healthcare provider may recommend either an office endometrial biopsy or a minor surgical procedure called a hysteroscopy with a curettage or sampling of the endometrium.

Endometrial hyperplasia cannot be diagnosed by a blood test or an ultrasound. However, it is possible that your healthcare provider may recommend certain blood tests to rule out other causes of abnormal uterine bleeding.

It is also possible that your healthcare provider may order a transvaginal pelvic ultrasound to help in the diagnosis of the cause of your abnormal uterine bleeding.

Endometrial hyperplasia can only be diagnosed after your endometrium has been sampled and evaluated under the microscope by a pathologist.

Endometrial Biopsy

In an endometrial biopsy, your healthcare provider removes a small amount of tissue from the endometrium. This tissue is examined under a microscope for abnormal cells.

This is a very common office-based gynecologic procedure. In general, it is very well-tolerated. Anticipation and anxiety of having the procedure are often much worse than the actual biopsy.

If you need to have an endometrial biopsy, it is a good idea to take 600 mg of ibuprofen and have a little snack about an hour before the procedure. You may want to bring a small warm pack or patch with you to help minimize cramping during and after the procedure. Your healthcare provider may even give you one at the time of the biopsy.

The set-up for the biopsy is the same as for a routine pap smear. A medical tool called a speculum is placed to help your doctor view the cervix, the lower end of the uterus. Your healthcare provider will clean off your cervix with a gentle antiseptic. They will place a grasper to hold your cervix in place while a small aspirator device is inserted to collect the tissue.

You will likely experience some discomfort. You won’t feel anything sharp, but you will have some cramping. The discomfort can range from mild period cramps to intense cramping similar to early labor pains.

The procedure is quick and typically lasts less than one minute. Taking ibuprofen before the procedure and using a warm pack during the procedure helps minimize the pain.


In an endometrial biopsy, your healthcare provider collects a small sample of tissue from your endometrium to view under a microscope. It's usually done in the gynecologist's office. You may be asked to take ibuprofen before the procedure to help minimize any pain.


Your healthcare provider may suggest that you undergo a hysteroscopy and endometrial sampling instead of an endometrial biopsy.

This is a same-day surgical procedure. In some gynecologic practices, it is also performed in the office instead of the operating room.

The benefit of hysteroscopy is that it allows your healthcare provider to directly observe the lining of the uterus. This helps make sure that all areas of the endometrium are adequately sampled.


A hysteroscopy is a same-day surgical procedure. It allows your healthcare provider to inspect the endometrium while getting tissue samples.

Types of Endometrial Hyperplasia

When the pathologist looks at the sample of your endometrium under the microscope they look specifically at changes in the two components of your endometrium, the glands and the supportive tissue called stroma.

Endometrial hyperplasia is diagnosed when there are more glands relative to stroma than you would find in normal proliferative or cycling endometrium.

The pathologist will then comment on whether there are atypical appearing cells in this abnormally thickened endometrium. This leads to two classifications of endometrial hyperplasia:

  • Hyperplasia without atypia, which has normal-looking cells
  • Atypical hyperplasia, which has abnormal cells that are considered precancerous

Endometrial hyperplasia is not endometrial cancer, but it may be considered a precancerous condition. In fact, in some cases of significant atypical hyperplasia, a very early stage endometrial cancer may already be present.


It is very important that all endometrial hyperplasia be closely followed or treated. The course of treatment will depend on whether or not there is atypia, or abnormal cells.

Endometrial Hyperplasia Without Atypia

When there are no atypical cells present, the chance of endometrial hyperplasia eventually becoming endometrial cancer is very unlikely. The evidence suggests that only about 5% of women with endometrial hyperplasia without atypia will develop endometrial cancer. It is also likely that this type of endometrial hyperplasia will resolve on its own over time.

Modifying Risk Factors

The first line of treatment is to look for risk factors that you can change. For example, if you are significantly overweight or obese, losing weight will help decrease the excess estrogen produced by fat cells. This will allow the lining of your uterus to reset itself.

If you're taking hormone replacement therapy, your healthcare provider may need to adjust your dose or recommend that you discontinue using it.


Your healthcare provider may recommend using progestin treatments to counteract the thickening effect of the excess estrogen on your endometrium. Reasons your healthcare provider may suggest treating you with progestin include:

  • Observation and lifestyle changes didn’t work.
  • You are having abnormal uterine bleeding.
  • You want the fastest result.

An oral progesterone or a progesterone-containing IUD may be suggested for the treatment of endometrial hyperplasia without atypia. This can include the levonorgestrel IUD (Mirena).

If your BMI is over 35, the progesterone treatment may not work well unless you also lose weight. You should discuss with your healthcare provider which type of progesterone treatment is best for you.

Whether you chose observation or treatment with progesterone, you will have to be followed closely with interval endometrial sampling. This helps to assure that the endometrial hyperplasia is gone and doesn’t come back.


Experts say that a hysterectomy should not be offered as a first-line treatment option for endometrial hyperplasia without atypia. That's because of the overall effectiveness of progesterone treatment and the low risk of developing endometrial cancer.

However, there are certain situations where a hysterectomy may be an appropriate treatment option for women who are done having children. Your healthcare provider may recommend a hysterectomy if:

  • During follow-up, you develop atypical hyperplasia
  • The hyperplasia does not improve after 12 months of progesterone treatment
  • You are having significant abnormal bleeding
  • You develop endometrial hyperplasia again after it was successfully treated
  • You do not want to undergo the repeat endometrial biopsies required with progesterone treatment.

Endometrial Hyperplasia With Atypia

If you have hyperplasia with atypia, there is a much more significant risk of developing endometrial cancer. Treatment is a bit more aggressive because of that increased risk. In fact, experts recommend hysterectomy as the first-line treatment for atypical hyperplasia in women who are done having children.

If you are diagnosed with atypical hyperplasia and planning on trying to get pregnant, you will likely be treated with progesterone. Preferably, this would be with the levonorgestrel IUD.

You will have more frequent endometrial sampling to assure that the atypical hyperplasia has been treated adequately. Your healthcare provider may suggest you see a fertility specialist to complete your childbearing as soon as you possibly can.

Your healthcare provider will likely suggest having a hysterectomy after you are done having children. That's because atypical endometrial hyperplasia has a high likelihood of recurrence.


To treat endometrial hyperplasia without atypia, your healthcare provider may recommend losing weight, discontinuing hormone replacement therapy, or using progestin treatments. If you have hyperplasia with atypia, a hysterectomy will likely be recommended.


Endometrial hyperplasia is caused by a hormone imbalance that allows your endometrium to thicken and develop abnormal changes. This can lead to irregular bleeding that may be heavier than normal, in between periods, or after menopause.

If endometrial hyperplasia is suspected, your healthcare provider will likely recommend a biopsy of your uterine lining. Endometrial hyperplasia can be classified as one of two types. Hyperplasia without atypia has normal-looking cells, and atypical hyperplasia has abnormal cells considered precancerous.

In hyperplasia without atypia, treatment may include risk factor management, such as losing weight or discontinuing hormone therapy. You may also take progesterone treatments.

If you have atypical hyperplasia, a precancerous condition, your doctor may recommend a hysterectomy. If you're still planning on getting pregnant, your doctor may suggest progesterone treatments along with frequent monitoring of your condition.

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6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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