Increased endometrial thickness is a potential sign of endometrial cancer. Doctors are most likely to be concerned if you also experience bleeding.
Endometrial thickness refers to the thickness of the lining of your uterus. The thickness normally varies throughout your menstrual cycle. For most postmenopausal women, it’s generally 3 millimeters or less. Exceeding this threshold can be a sign of cancer, although many women with increased thickness don’t have cancer.
Endometrial thickness is measured with a transvaginal ultrasound. You might receive an ultrasound to screen for cancer if you experience bleeding, but the American College of Obstetricians and Gynecologists (ACOG) doesn’t recommend ultrasound as a screening tool for women without bleeding.
Read on to learn more about what your endometrial thickness measurements may mean and what to expect next.
The typical endometrial thickness after menopause is 3 millimeters or less for individuals not on hormone replacement therapy (HRT). About 3–15% of postmenopausal women have endometrial thickening over this threshold without symptoms. Endometrial thickness generally decreases over time, and it often takes several years after menopause to stabilize.
HRT, especially estrogen, can cause your endometrium to become thicker. The acceptable endometrial thickness for women on hormone therapy is less defined, but it’s been suggested that thicknesses of 8–11 millimeters are acceptable.
You may receive an ultrasound as a screening tool to measure the thickness of your uterus if you’ve experienced bleeding. A high endometrial thickness can be a sign of endometrial cancer, but it isn’t enough to diagnose cancer by itself.
If your endometrial wall is over 3 millimeters, your doctor may send you for a biopsy to monitor for cancer. Recent recommendations for Black women are that thinner linings are not as predictive.
If you don’t have bleeding or if you’re on HRT, your doctor is unlikely to refer you for imaging unless you exceed about 11 millimeters. Endometrial cancer is rare in individuals who don’t have postmenopausal bleeding. More than 90% of individuals with endometrial cancer experience these symptoms.
About 3–15% of postmenopausal women have endometrial thickening that isn’t caused by cancer, which is also called benign endometrial hyperplasia. It’s usually caused by excess estrogen.
More than 90% of women with endometrial cancer have bleeding. Noticing bleeding can be concerning, but only about 9% of women who experience it have cancer, and the vast majority of people with a thickened endometrium don’t have cancer.
Warning signs
Potential warning signs of endometrial cancer include:
- bleeding, even if it seems minor
- pelvic pain or lower abdominal pain
- painful intercourse
- unintentional weight loss
- anemia, which might cause light-headedness or fatigue
- unexplained urinary or bowel changes
It’s important to talk with your doctor if you experience these symptoms, even if your bleeding is only light spotting.
Hormone therapy may include estrogen, progesterone, or a combination of both. An abundance of estrogen causes endometrial hyperplasia, or thickening of the endometrium. Generally, an endometrial thickness of up to 8–11 millimeters is still considered acceptable for women on HRT.
Trans men who still have female genitalia may have thinner endometria than cis women if they’re receiving testosterone hormone therapy.
Potential risk factors for endometrial thickness include:
- increasing age
- obesity, which seems to be a particularly strong risk factor
- high blood pressure
- smoking
- Lynch syndrome
- tamoxifen use
- diabetes
- estrogen therapy alone or menopause hormone therapy (MHT)
- a family history of gynecological cancers
Endometrial thickness is primarily measured with a test called a transvaginal ultrasound, where an ultrasound is inserted into your vaginal to create an image of your uterus.
If your doctor is concerned by the thickness of your endometrial wall and you have bleeding, they may order a biopsy where they take a small tissue sample. The most common technique is the Pipelle biopsy, which takes the sample with a long, thin tube. This procedure can often be done in your doctor’s office.
Studies have reported that this test can accurately diagnose cancer in more than 99% of cases.
If you don’t have bleeding, your doctor may not recommend a biopsy unless your endometrium is much thicker than normal.
Sometimes doctors use a technique called hysteroscopy instead of a Pipelle biopsy to make the diagnosis. This test involves inserting a long, thin tube with a camera into your uterus to examine cells and potentially collect a biopsy. There remains controversy over whether this technique may spread cancer cells; however, it has
If biopsy results are unclear, your doctor may recommend dilation and curettage, where your cervix is dilated and tissue is removed for examination.
If your test results suggest that you don’t have cancer, you may be given progestin to help treat your symptoms. This medication may be administered:
- orally
- through an intrauterine device (IUD)
- via an injection
- through vaginal cream
Your doctor may recommend monitoring alone if you’re not experiencing symptoms. If they’re worried that you could develop cancer later, they may recommend a hysterectomy, the removal of your uterus.
The main surgery for endometrial cancer is hysterectomy. Other
- radiation therapy
- chemotherapy
- hormone therapy
- targeted therapy
- immunotherapy
You’ll likely need regular follow-ups after your treatment to make sure that it’s effective and to make sure your cancer doesn’t come back.
Most health experts, such as the ACOG, don’t recommend screening with ultrasound if you don’t have symptoms of endometrial cancer. They usually only recommend an ultrasound if you have bleeding.
You can’t always prevent endometrial thickening, but you can help reduce your chances of developing some of the risk factors, such as diabetes or obesity, by:
- reducing stress
- eating a balanced diet
- exercising regularly
It’s also important to seek medical attention right away if you experience potential symptoms of cancer.
Endometrial thickness is a metric doctors use to assess your risk of endometrial cancer. It’s not enough to diagnose cancer by itself, but the results can be suggestive if you have other symptoms such as bleeding.
It’s important to seek medical attention if you experience bleeding after menopause. Bleeding usually isn’t a sign of cancer, but almost all women who do develop endometrial cancer experience bleeding.