Fibroids 101

Visit our glossary to see definitions of terms.

What are uterine fibroids?compare-uf_fibroids-101_types_12oct2015

Fibroids are not cancer, though you may hear them referred to as “tumors.”

Uterine fibroids are growths that develop in the uterus: inside, outside, or in the muscle.

Some women have one; some have many. Some are large; some are small. The number of fibroids and their size depends on the presence of female hormones estrogen and progesterone. When these hormones decrease after menopause, fibroids often shrink.


compare-uf_study_the-problem_13oct2015Who gets fibroids?

Did you know that ~75% of all women have fibroids? And the incidence is even higher in African-American women (~85%). But not all women have symptoms such as bleeding or pain, so may never know that they have them.

Is treatment necessary?

Fibroids that do not cause symptoms do not require any treatment. But fibroids are the most common non-cancer reason why women are hospitalized in the U.S.

Fibroids are also the most common reason for hysterectomy (removal of the uterus), and hysterectomy is the second most common surgical procedure performed in women (first is c-section to deliver a baby).

Learn about treatment options


What are some common symptoms?compare-uf_fibroids-101_symptoms-complications_13oct2015

Heavy menstrual bleeding and bleeding in-between menstrual periods are the most common symptom. The bleeding may be heavy enough to cause anemia (low blood count) and can have great impact on a woman’s quality of life. Some woman always carry a black sweater to hide ‘accidents’, or wear pads every day—just in case.

Pain during and in-between menstrual periods may be severe, depending on the size and location of the fibroids.

Bladder and bowel symptoms (such as needing to use the bathroom more frequently or having difficulty going to the bathroom) may occur depending on the size and location of the fibroids.

Fertility issues such as difficulty becoming pregnant or delivering a baby early.

Why do symptoms matter?

Symptomatic fibroids affect a woman’s quality of life, and women having symptoms may be less productive at work and at home.

There is a significant cost. A woman may spend over $300 per year on medications and supplies to manage fibroid symptoms. Nationally, the estimate of direct medical costs is 4–9 billion, and nonmedical cost of 2–17 billion.

Are there racial disparities?

Compared with white women, African-American women—

  • Are more likely to have fibroids (with and without symptoms)
  • Develop fibroids at a younger age
  • Have more severe disease (larger fibroids, more severe symptoms)
  • Are more likely to experience treatment complications

Why? We don’t know. This is one of the questions we hope to answer with the COMPARE-UF registry.

Learn more about fibroids on this FAQ sheet from