What are uterine fibroids?

Uterine fibroids are benign growths that are made up of the muscle and connective tissue from the wall of the uterus (womb). Fibroids may grow as a single nodule or in clusters and may range in size from 1 mm to more than 20 cm (8 inches) in diameter. They may grow within the wall of the uterus or they may project into the interior cavity or toward the outer surface of the uterus. In rare cases, they may grow on stems projecting from the surface of the uterus. Each patient with fibroids may have varying symptoms, sizes, number, and location. Each fibroid is unique and one of a kind, which requires individualization of therapeutic options.

Are fibroids cancer?

It is extremely rare for a fibroid to undergo malignant or cancerous changes. In fact, one out of 350 women with fibroids will develop malignancy. There is no test that is 100% predictive in detecting rare fibroid related cancers. However, patients who have rapid growth of uterine fibroids, or fibroids that grow during menopause, should be evaluated immediately.

Who is at risk for uterine fibroids?

Risk factors for uterine fibroids include obesity, family history, not having children, early onset of menstruation, and late age for menopause. (A person is considered obese if he or she is more than 20% over his or her ideal body weight.)

What causes uterine fibroids?

The causes of fibroids are not known. Most fibroids occur in women of reproductive age, and according to some estimates, they are diagnosed in black women 2-3 times more frequently than in white women. They seldom are seen in young women who have not begun to menstruate. The symptoms of uterine fibroids usually stabilize or go away in women after menopause.

According to the U.S. National Institutes of Health (NIH), 25%-80% of women suffer from uterine fibroids.

What are the symptoms of uterine fibroids?

Most fibroids do not cause any symptoms and do not require treatment other than regular observation by a doctor. Fibroids may be discovered during routine gynecologic examinations or during prenatal care. Some women who have uterine fibroids may have the following symptoms:

  • Excessive or painful bleeding during menstruation
  • Bleeding between periods.
  • A feeling of fullness in the lower abdomen
  • Frequent urination resulting from a fibroid that compresses the bladder
  • Pain during sexual intercourse
  • Low back pain
  • Constipation
  • Chronic vaginal discharge
  • Inability to urinate
  • Severe menstrual cramps
  • Infertility

Last reviewed by a Cleveland Clinic medical professional on 04/05/2017.


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