What Is the Normal Endometrial Thickness in Women?

Medically Reviewed on 10/29/2021
thickness women
The normal range of endometrial thickness depends on the stage of life you’re in. Here are the normal ranges for premenopausal and postmenopausal women.

Endometrial thickness varies according to a woman's age and menstrual cycle. A healthy endometrium is essential for a healthy pregnancy.

  • An endometrial thickness of less than 14 mm is typically considered normal at any stage of the menstrual cycle.
  • During menstruation, the endometrial thickness of pre-menopausal women ranges between two and four millimeters.
  • The endometrial thickness increases to between five and seven millimeters during the early proliferative stage, which occurs immediately after menstruation, usually between days four and seven. 
  • The endometrial thickness is approximately 11 mm in the late proliferative phase, which lasts for about 11 to 14 days. The glands will coil and become tightly packed together during this phase.
  • During the luteal or secretory phase, endometrial thickness grows to an average of 12 to 13 mm, which lasts from days 14 to 28.
  • The endometrial thickness is typically less than five millimeters in postmenopausal women who are not on hormone therapy.
  • However, the endometrial thickness in women who are on hormone therapy can reach up to 15 mm. Any higher value must be investigated.

Women must have a certain amount of endometrial thickness to conceive. Several issues can arise if the endometrium is not thick enough.

The best chances for a healthy, full-term pregnancy, according to medical experts, are associated with an endometrium that is neither too thin nor too thick. This allows the embryo to successfully implant and receives the nutrition it requires.

Good pregnancy rates have been reported in cycles with endometrium thicknesses of six millimeters although successful pregnancies have been reported with an endometrial thickness of four millimeters.

What does a thin endometrium mean?

The endometrium is the lining of the uterus. When the ovaries release an egg each month, the endometrium (uterine lining) thickens in preparation for the development of an embryo.

A thin endometrium occurs when the endometrium is less than seven millimeters thick. These complications can affect 1 to 2.5 percent of pregnant women.

Two hormones are involved in the formation of the endometrium.

  • Estrogen: Contributes to the formation of the endometrium
  • Progesterone: Aids in embryo implantation

Reasons for a thin endometrium include:

What is endometrial hyperplasia?

In some women, the endometrium thickens, resulting in unusual bleeding, which is known as endometrial hyperplasia. Depending on the presence of cells on the layer, endometrial hyperplasia can be cancerous or benign. It can sometimes be a sign of uterine or endometrial cancer.

Endometrial hyperplasia symptoms may include:

  • Unexplained uterine bleeding
  • Periods lasting more than five days, accompanied by heavy bleeding
  • The time between periods becomes shorter and could fall below 21 days
  • Women who have reached menopause may experience vaginal bleeding

Endometrial hyperplasia can be treated with both medications and surgery. The best options for you will be determined by the type of endometrial hyperplasia you have and your unique circumstances.


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What is endometriosis?

Endometriosis is the presence of normal endometrial mucosa (glands and stroma) in locations other than the uterine cavity. It affects 6 to 10 percent of women in the United States with approximately 4 per every 1,000 cases requiring hospitalization each year. The presence of tender masses along the thickened uterus is the most common finding on examination.

Endometriosis symptoms may include:

How is endometriosis treated?

Treatment of endometriosis may depend on the severity of the person’s condition, age, and whether they are planning to have children, as well as any other associated conditions.


  • Hormonal therapy can help slow the progression of endometriosis by interfering with local estrogen formation within endometrial growths.
  • Over-the-counter pain relievers can be used to treat pelvic pain and menstrual cramping.


  • Surgery may be recommended for some women who are trying to conceive or who have severe pelvic pain. Conservative surgery involves the removal of endometrial growths, scar tissue, and adhesions without the removal of reproductive organs. This can be done laparoscopically.
  • In the most severe cases, a surgeon will perform a hysterectomy with or without ovulation removal. This is usually used as a last resort, especially for women who are still in their reproductive years.
  • Although surgery can be very effective in treating endometriosis, the recurrence rate after surgery is estimated to be 40 percent.
Medically Reviewed on 10/29/2021
Image Source: Magryt / Getty Images

How thick is too thick? When endometrial thickness should prompt biopsy in postmenopausal women without vaginal bleeding: https://pubmed.ncbi.nlm.nih.gov/15386607/

Endometrial thickness: https://pubs.rsna.org/doi/10.1148/radiology.180.2.1829843

Endometriosis: https://emedicine.medscape.com/article/271899-overview