Risk Factors for Endometrial Hyperplasia

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Endometrial hyperplasia is an abnormality of the lining of your uterus or endometrium. You may experience symptoms of abnormal uterine bleeding in this condition, which results from a hormonal imbalance. A diagnostic workup can show whether you have atypical cells, which will guide the course of treatment.

Nurse holding a model of a uterus
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The Endometrium

Your endometrium is what builds up and sheds each month in response to your regular cyclic hormonal changes. It is the major component of your monthly menstrual flow. It is completely normal for the lining of your uterus to get thicker or proliferate during the first half of your menstrual cycle.

Your ovaries normally produce estrogen and progesterone in response to stimulating hormones from the brain. This organized and well-timed change and balance of estrogen and progesterone are what makes your period come regularly, roughly every 28 days.

If there is an imbalance in the hormonal stimulation of the endometrium, an abnormality can occur. This abnormal change is an irregular thickening of the endometrium and is called endometrial hyperplasia.

Endometrial Hyperplasia Symptoms

Symptoms are abnormal uterine bleeding such as:

  • 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, it is important to 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 that there is a relative excess of estrogen 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 not allowing for extra, abnormal growth. When there is a relative excess of estrogen the lining is overstimulated and continues to thicken. Over time, that thickened lining begins to develop abnormal changes.

Risk Factors

Conditions that cause estrogen excess 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 cyclic estrogen produced by your ovaries. If your BMI is over 35, you have a significantly increased risk of developing endometrial hyperplasia compared to you at an ideal body weight. 


There can be several reasons why you may not ovulate. If you do not ovulate your ovary will not 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 lack of a bump in progesterone allows for a relative excess of estrogen. This unbalanced estrogen results in an abnormal thickening of the endometrium. Eventually, you will have some type of abnormal uterine bleeding.

Typical bleeding patterns with this type of anovulation include irregular and heavy periods or bleeding between your periods. Common causes of this type of hormonal imbalance include:

Exogenous Hormones

Obviously taking estrogen replacement will increase your estrogen levels relative to your progesterone levels. That is why if you still have a uterus you need to take some form of a progestin (progesterone) to prevent your endometrium from being overstimulated when taking estrogen.

Another hormonal medication that can cause an 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 because it opposes the effects of estrogen in the breast tissue. However, Tamoxifen stimulates the estrogen receptors in the lining of the uterus so it acts like an estrogen and can cause endometrial hyperplasia.

If you are using hormone replacement therapy or Tamoxifen and you develop abnormal uterine bleeding, it is very important that you see your healthcare provider and be evaluated.

Estrogen-Producing Ovarian Tumors

Hormone-producing tumors are not a very 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 it is likely that you will undergo a biopsy of the lining of your uterus. 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 Biopsy

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 also 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. After the speculum is placed your healthcare provider will clean off your cervix with a gentle antiseptic. Likely your healthcare provider will then place a grasper to hold your cervix in place while the small aspirator device is inserted.

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 good news is the procedure is quite quick and typically lasts less than one minute. Taking ibuprofen before the procedure and using a warm pack during the procedure definitely helps minimize the 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 and 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 assure that all areas of the endometrium are adequately sampled. There can be certain situations in which your healthcare provider may suggest this slightly more invasive procedure.

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.


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 leading to the two classifications of endometrial hyperplasia:

  • Hyperplasia without atypia
  • Atypical hyperplasia

Endometrial hyperplasia is not endometrial cancer but it is 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.

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.

Target Risk Factors

The first line of treatment is to look for risk factors that are modifiable. 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.

Similarly, if you are taking hormone replacement therapy your healthcare provider may either 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 progesterone include:

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

The two types of progesterone suggested for the treatment of endometrial hyperplasia without atypia are oral progesterone or a progesterone-containing IUD. The evidence favors using the levonorgestrel IUD (Mirena).

If your BMI is over 35, it is more likely that progesterone treatment will 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 to assure that the endometrial hyperplasia is gone and doesn’t come back.


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

However, experts agree that there are certain situations in which a hysterectomy may be the most 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

There is a much more significant risk of developing endometrial cancer if you have hyperplasia with atypia. The management 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 have been diagnosed with atypical hyperplasia and are still planning on trying to get pregnant, you will likely be treated with progesterone, preferably with the levonorgestrel IUD.

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

It is likely that your healthcare provider will suggest having a hysterectomy after you are done having children because of the high likelihood of recurrence of atypical endometrial hyperplasia.

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6 Sources
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