What is Endometrial Hyperplasia?

Endometrial hyperplasia is the thickening of the uterine endometrium (lining of the uterus). The two classifications of endometrial hyperplasia are simple or complex and is additionally classified by changes on the cellular level and is termed atypical in the presence of abnormal cellular changes.

The four types of hyperplasia include the following:

  • Simple hyperplasia
  • Complex hyperplasia
  • Simple complex hyperplasia
  • Complex atypical hyperplasia

The most common form of endometrial hyperplasia is mild hyperplasia which carries a low risk of developing into endometrial cancer. This form may self resolve or resolve with hormonal treatment. The more concerning hyperplasia, referred to as atypical, carries a higher risk of developing into cancer. Simple atypical hyperplasia carries an 8% risk of cancer if left untreated whereas complex atypical hyperplasia carries an approximately 29% risk of cancer development.

Endometrial Hyperplasia Causes and Risk Factors

Hormones are responsible for changing the appearance of the lining of the uterus during the menstrual cycle. Estrogen is responsible for making the lining thick which is in preparation for an impending pregnancy whereas progesterone which is excreted following ovulation, supports the actual pregnancy. When a pregnancy is not present, these two hormones decrease and menstruation occurs. During this time in the menstrual cycle, the lining of the uterus is shed and expelled from the body. When there is a disruption in this cycle of hormonal regulation, abnormalities in the menstrual cycle are likely to occur. In the case of endometrial hyperplasia, the most common cause is the presence of excessive estrogen without progesterone causing the lining of the uterus to continue to thicken and not shed.

Endometrial hyperplasia is a condition which usually presents following menopause however it can also occur during the perimenopausal period. Other instances in which endometrial hyperplasia can occur include the use of estrogen-like medication, long-term, high dose use of postmenopausal estrogen when a woman has not had her uterus removed, conditions such as polycystic ovarian syndrome (PCOS) in which women experience irregular menstrual cycles or in instances of infertility. Additionally women who are obese are at a higher risk of developing endometrial hyperplasia.

Certain women are at a higher risk of developing the condition and include:

  • Age (women 35 and older)
  • Race (women of the white race)
  • No prior history of pregnancy
  • Early initiation or late cessation of menses
  • Medical conditions such as obesity, diabetes, PCOS, gallbladder disease, or the presence of thyroid disease
  • Smoking
  • Family history of certain cancers including that of the ovary, cervix or uterus

There are steps you can take to decrease your risk of developing endometrial hyperplasia. These include maintaining a healthy weight to avoid obesity, using birth control pills to regulate irregular menstrual cycles and taking progestin or progesterone when post menopausal estrogen is used.

It is important that you discuss your personal risk factors and best methods of prevention with your medical provider.

Endometrial Hyperplasia Symptoms

Abnormal uterine bleeding is the most common symptom experienced by women with endometrial hyperplasia however other symptoms may also be present and include heavier than normal or longer in duration menstrual periods, menstrual cycles which are less than 21 days and/or post menopausal bleeding.

Endometrial Hyperplasia Diagnosis and Treatment

Your healthcare provider may perform certain tests to determine what is causing your abnormal symptoms and may include a transvaginal ultrasound, an endometrial biopsy, dilation and curettage and/or hysteroscopy.

Treatment of endometrial hyperplasia will depend on your personal situation however it is most commonly treated with the use of progestin via pill, injection, vaginal cream or via an intrauterine device. In cases where certain types of atypical hyperplasia is present, hysterectomy may be recommended.


  1. Endometrial Hyperplasia. American Congress of Obstetricians and Gynecologists. Accessed April 8, 2015. Endometrial Hyperplasia.
  2. What are the risk factors for endometrial cancer? American Cancer Society. Accessed April 8, 2015.
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