A fibroid is a noncancerous tumor of the uterus that is composed of muscle and fibrous tissue.
Uterine fibroids are very common, occurring in approximately 70% of White women and 80% of Black women in the United States.
Fibroids may cause no symptoms or can cause abnormal uterine bleeding or pressure or pain in the pelvis, and sometimes constipation, an urge to urinate frequently, infertility, or pregnancy complications.
Doctors do a pelvic examination and usually ultrasonography to confirm the diagnosis.
Treatment is necessary only if fibroids cause problems.
Doctors may prescribe medications to control the symptoms, but surgery or a procedure to destroy or remove the fibroids is often needed to relieve symptoms or to improve fertility.
Fibroids
Fibroids
(U.S. Navy photograph)
Fibroids are also called leiomyomas or myomas.
The Uterus, Cervix, and Cervical Canal
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Fibroids in the uterus are the most common noncancerous tumor (mass) of the female reproductive tract. By age 45, about 70% of women develop at least one fibroid. Many fibroids are small and cause no symptoms. But about one half of Black women and one fourth of White women eventually develop fibroids that cause symptoms.
Did You Know...
By age 45, about 7 out of 10 women develop fibroids of the uterus.
The cause of fibroids is unknown. High levels of estrogen and possibly progesterone (female hormones) seem to stimulate their growth. Fibroids may become larger during pregnancy (when levels of these hormones increase), and fibroids tend to shrink after menopause (when levels decrease drastically).
Fibroids may be microscopic or as large as a basketball. Many women have more than one fibroid. Sometimes, if fibroids grow too large, they may not be able to get enough blood. As a result, they begin to degenerate (tissue starts to die without enough blood supply), and this causes pain.
Fibroids may grow in different parts of the uterus, usually in the wall (which has three layers):
Under the outer surface of the uterus (subserosal fibroids)
In the wall of the uterus (intramural fibroids)
Under the inside layer (lining or endometrium) of the uterus (submucosal fibroids)
Sometimes fibroids grow in other locations, such as the cervix (bottom part of the uterus) or the broad ligament (connective tissue that surrounds the uterus).
Fibroids may be contained completely within the wall of the uterus, or they may protrude into other areas of the body. Fibroids can vary in shape. Some fibroids grow from a stalk (called pedunculated fibroids) and can protrude into the abdominal cavity, which can cause pressure on surrounding organs, such as the intestines or bladder. Some fibroids extend into the interior of the uterus (called intracavitary fibroids).
Some cancerous tumors of the uterus look similar to fibroids on imaging studies and may cause similar symptoms, such as abnormal bleeding. These cancerous tumors are rare, occurring in fewer than 1% of women with uterine masses that look similar to fibroids. Doctors do further evaluation if cancer is suspected. Based on current research, it is not thought that the typical type of fibroid changes and develops into cancer.
