What is endometrial hyperplasia and why does it occur?

By (gynecologist), (embryologist), (embryologist), (gynecologist), (gynecologist) and (psychologist).
Last Update: 11/25/2022

Endometrial hyperplasia is the excessive proliferation of the cells that make up the endometrium. In general, this endometrial alteration is caused by a hormonal imbalance between estrogen and progesterone values.

The most prominent sign that raises suspicion of possible endometrial hyperplasia is abnormal vaginal bleeding, although it is not a specific clinical manifestation of this disorder.

On the other hand, endometrial hyperplasia is classified into 4 different types: simple, complex, atypical simple, and atypical complex. In any case, the most important thing is to diagnose, control and treat this endometrial thickening to prevent it from progressing to endometrial cancer.

What is endometrial hyperplasia?

Endometrial hyperplasia consists of an exaggerated growth of the cells that make up the superficial layer surrounding the uterus, i.e. the endometrium. This condition usually appears in women over 45 years of age.

Generally, excessive proliferation of endometrial cells is associated with elevated estrogen levels in women in combination with decreased progesterone values.

These hormones (estrogen and progesterone) act on the woman's menstrual cycle. The purpose of estrogens is to provoke cell growth of the endometrium, while progesterone indicates the moment of endometrial detachment.

For this reason, an imbalance in estrogen and progesterone values may be the cause of excessive and abnormal proliferation of endometrial cells.

Risk Factors

As in any other medical pathology, there are risk factors that increase the probability of endometrial hyperplasia in women. Some of these risk factors are listed below:

  • Follicular persistence and as a result the appearance of cysts within the ovary.
  • Cirrhosis of the liver, i.e., the last stage of liver disease.
  • Adrenal tumors.
  • Polyps in the cervix.
  • Presence of myomas in the uterus
  • Endometriosis.

On the other hand, scientific studies have found evidence that obesity and a family history of colon carcinoma are also associated as risk factors for endometrial hyperplasia.

However, it should be noted that having any of these risk factors does not mean that there is a 100% chance that a woman will develop endometrial hyperplasia.

Types of endometrial hyperplasia

The World Health Organization (WHO) established a classification of endometrial hyperplasia into three groups: cystic, adenomatous, and atypical. At present, this classification is not taken into account, but the types of endometrial hyperplasia are as follows:

Simple atypical endometrial hyperplasia
its risk of progression to endometrial carcinoma is 8% if not adequately treated.
Complex atypical endometrial hyperplasia
is the precursor form of endometrial carcinoma. This type of hyperplasia usually progresses to endometrial cancer in 29% of cases.
Simple non-atypical endometrial hyperplasia
it is a benign proliferation with an increase in the number of endometrial glands, but without cytologic atypia.
Complex non-atypical endometrial hyperplasia
the risk of progression to endometrial cancer is 3% in approximately 10 years. In this case, the endometrial glands have irregular contours and are agglomerated.

In any case, each form of endometrial hyperplasia has certain morphologic features that aid in diagnosis. Despite being a benign alteration, it is essential to diagnose endometrial thickening to avoid progression over time to cancer.

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The main symptom that makes a specialist suspect possible endometrial hyperplasia is an altered menstruation. Other manifestations in women that may be indicative of endometrial hyperplasia include the following:

  • Abundant menstrual bleeding, both in quantity and duration.
  • Short menstrual cycles, less than 21 days.
  • Bleeding between periods.
  • Uterine bleeding after menopause.

However, many women with endometrial hyperplasia do not show any symptoms. Therefore, there are cases of endometrial hyperplasia that are totally asymptomatic.


As we have already mentioned, the detection of endometrial hyperplasia in women is important, as it can progress to cancer. In addition, endometrial hyperplasia causes uterine bleeding and is indicative of possible polycystic ovarian syndrome (PCOS).

Mainly, the diagnosis of endometrial hyperplasia in a woman is basically histological and will be made through 3 medical tests:

is performed through the vagina and the gynecologist will measure the thickness of the endometrium. If the endometrium is too thick, it is an indication of possible endometrial hyperplasia.
Endometrial biopsy
to obtain a sample of the endometrium to be analyzed in the laboratory cell histology.
a test that allows visualization of the uterine cavity and mucous membranes, in addition to helping if combined with endometrial biopsy.

Diagnostic studies can also be completed with the observation of abnormal glandular cells by means of a pap smear.

Treatment of endometrial hyperplasia

The best treatment for endometrial hyperplasia will depend on the type of hyperplasia diagnosed and the woman's desire for future pregnancy. In addition, it is also important to take into account the patient's age and the existence of other associated pathologies.

In the case of women diagnosed with endometrial hyperplasia and who want to have offspring, treatment will consist of administering contraceptive pills or progesterone. These women should visit their gynecologist periodically for ultrasound examinations.

For women diagnosed with atypical endometrial hyperplasia and women who do not desire a future pregnancy, most specialists propose the removal of the uterus. Hysterectomy in these cases prevents endometrial hyperplasia from progressing to cancer.

Another therapeutic alternative for endometrial hyperplasia is to perform curettage followed by pharmacological treatment with progestogens.

FAQs from users

Does endometrial hyperplasia affect fertility?

By Gustavo Daniel Carti M.D. (gynecologist).

Endometrial hyperplasia is a condition of the endometrium characterized by exaggerated proliferation. This condition can affect the endometrium as a whole or in a focal form constituting the so-called endometrial polyps.

In any case, abnormal proliferations of the endometrial tissue should be observed and sometimes a biopsy is recommended to rule out complex pathologies.

The endometrium is the biological tissue where the embryo will nest. For this reason, an abnormal development of the endometrium will generate an extremely hostile and inadequate terrain for gestation to take place.

Are there other symptoms associated with endometrial hyperplasia besides abnormal bleeding?

By Rubén Baltá I Arandes M.D. (gynecologist).

The main clinical manifestation of endometrial hyperplasia is abnormal uterine bleeding, and in approximately 15% of patients with a history of abnormal uterine bleeding, a diagnosis of some form of hyperplasia is made.

In some cases, endometrial hyperplasia may present with fever, severe abdominal pain or abdominal swelling, but may also be asymptomatic. If endometrial thickening occurs in young patients, it may cause infertility due to a non-functioning endometrium.

Is pregnancy possible with endometrial hyperplasi

By Paula Cano Calvo B.Sc., M.Sc. (embryologist).

The embryologist Paula Cano from Pronatal clinics in Madrid tells us if it is possible to achieve a pregnancy with endometrial hyperplasia:

Endometrial hyperplasia is an abnormal or excessive growth of the endometrium caused mainly by a hormonal imbalance between oestrogen and progesterone levels. These two hormones prepare the endometrium and cause it to grow until it reaches a thickness of about 6-10 mm, at which point it is ready to receive the embryo and which is called the window of implantation. When there is abnormal growth of the endometrium, this can compromise pregnancy, as the endometrium is the tissue that lines the entire uterine cavity and is where the embryo implants. So if the thickness is not adequate, this implantation can be compromised. This is why when this alteration occurs, the patient should always see a specialist.

What is endometrial hyperplasia?

By Sergio Rogel Cayetano M.D. (gynecologist).

Endometrial hyperplasia is an uncontrolled growth of the endometrium, without this implying malignancy in its cells. Most of the time (although not always) it occurs due to excessive hormonal stimulation, for example, prolonged estrogen secretion or administration.

Endometrial hyperplasia, therefore, is nothing more than the situation in which the endometrium produces, as always in the first part of the cycle, before ovulation, cellular proliferation and growth of endometrial thickness, but in an excessive and disordered manner.
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Can endometrial hyperplasia be prevented?

By Marta Barranquero Gómez B.Sc., M.Sc. (embryologist).

No. Excessive proliferation of endometrial cells cannot be prevented, although the risk can be reduced. There are certain risk factors that could be avoided and, therefore, reduce the probability of developing endometrial hyperplasia. This is mainly the case with obesity and smoking.

As discussed in the article, endometrial hyperplasia may be indicative of PCOS. If you want to learn more about this syndrome, we recommend you to visit the following article: Polycystic ovary syndrome (PCOS): causes, symptoms, and treatment.

On the other hand, one way to diagnose this endometrial condition is by biopsy. If you are interested in this diagnostic test and want more in-depth information, do not forget to access this link: What is endometrial scratching - Indications and procedure.

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Auclair MH, Yong P, Salvador S, Thurston J, Terry J Colgan T, Sebastianelli A. Guideline No. 392-Classification and Management of Endometrial Hyperplasia. J Obstet Gynaecol Can. 2019 Dec;41(12):1789-1800. doi: 10.1016/j.jogc.2019.03.025 (View)

Armstrong AJ, W Hurd W, Elguero S, Barker N, Zanotti K. Diagnosis and management of endometrial hyperplasia. J Minim Invasive Gynecol. Sep-Oct 2012;19(5):562-71. doi: 10.1016/j.jmig.2012.05.009. Epub 2012 Aug 3 (View)

Chandra V Joo Kim J, Benbrook D, Dwivedi A, Rai R. Therapeutic options for management of endometrial hyperplasia. J Gynecol Oncol. 2016 Jan;27(1):e8. doi: 10.3802/jgo.2016.27.e8. Epub 2015 Dec 1 (View)

Dietel M. The histological diagnosis of endometrial hyperplasia. Is there a need to simplify? Virchows Arch. 2001 Nov;439(5):604-8. doi: 10.1007/s004280100503.

H Fox, C H Buckley. The endometrial hyperplasias and their relationship to endometrial neoplasia. Histopathology. 1982 Sep;6(5):493-510. doi: 10.1111/j.1365-2559.1982.tb02747.x.

Mi Byun J, Hoon Jeong D, Nam Kim Y, Bee Cho E, Eun Cha J, Su Sung M, Bok Lee K, Tae Kim K. Endometrial cancer arising from atypical complex hyperplasia: The significance in an endometrial biopsy and a diagnostic challenge. Obstet Gynecol Sci. 2015 Nov;58(6):468-74. doi: 10.5468/ogs.2015.58.6.468. Epub 2015 Nov 16.

Sobczuk K, Sobczuk A. New classification system of endometrial hyperplasia WHO 2014 and its clinical implications. Prz Menopauzalny. 2017 Sep;16(3):107-111. doi: 10.5114/pm.2017.70589.

FAQs from users: 'Does endometrial hyperplasia affect fertility?', 'Are there other symptoms associated with endometrial hyperplasia besides abnormal bleeding?', 'Is pregnancy possible with endometrial hyperplasi', 'What is endometrial hyperplasia?' and 'Can endometrial hyperplasia be prevented?'.

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Authors and contributors

 Gustavo Daniel  Carti
Gustavo Daniel Carti
Dr. Gustavo Daniel Carti has a degree in medicine and specialized in obstetrics and gynecology from the University of Buenos Aires. More information about Gustavo Daniel Carti
Licence number: 07/0711274
 Marta Barranquero Gómez
Marta Barranquero Gómez
B.Sc., M.Sc.
Graduated in Biochemistry and Biomedical Sciences by the University of Valencia (UV) and specialized in Assisted Reproduction by the University of Alcalá de Henares (UAH) in collaboration with Ginefiv and in Clinical Genetics by the University of Alcalá de Henares (UAH). More information about Marta Barranquero Gómez
License: 3316-CV
 Paula Cano Calvo
Paula Cano Calvo
B.Sc., M.Sc.
Paula Cano is currently an embryologist at Pronatal Fertility Clinics, a fertility center located in Madrid. Paula studied Biology at the University of Girona and did a Master's degree in Clinical Genetics and Assisted Human Reproduction at the University of Alcalá de Henares, Madrid. More information about Paula Cano Calvo
Member number: 20364-M
 Rubén  Baltá I Arandes
Rubén Baltá I Arandes
Dr. Rubén Baltá has a degree in Medicine and Surgery from the Autonomous University of Barcelona and a postgraduate specialization in Esthetic and Functional Gynecology and Women's Cosmetic Genital Surgery from the University of Barcelona. More information about Rubén Baltá I Arandes
Medical licence: 070709574
 Sergio Rogel Cayetano
Sergio Rogel Cayetano
Bachelor's Degree in Medicine from the Miguel Hernández University of Elche. Specialist in Obstetrics & Gynecology via M. I. R. at Hospital General de Alicante. He become an expert in Reproductive Medicine by working at different clinics of Alicante and Murcia, in Spain, until he joined the medical team of IVF Spain back in 2011. More information about Sergio Rogel Cayetano
License: 03-0309100
Adapted into english by:
 Cristina  Algarra Goosman
Cristina Algarra Goosman
B.Sc., M.Sc.
Graduated in Psychology by the University of Valencia (UV) and specialized in Clinical Psychology by the European University Center and specific training in Infertility: Legal, Medical and Psychosocial Aspects by University of Valencia (UV) and ADEIT.
More information about Cristina Algarra Goosman
Member number: CV16874

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