Uterine fibroids are benign (not cancer) growths in the uterus. They are the most common type of growth found in a woman’s pelvis. They occur in about 25 percent to 50 percent of all women.
Types of Fibroids
Uterine fibroids are growths that develop from the cells that make up the muscle of the uterus. They are also called leiomyomas or myomas.
The size, shape, and location of fibroids can vary greatly. They may appear inside the uterus, on its outer surface, within its wall, or attached to it by a stemlike structure.
Fibroids are most common in women aged 30-40 years, but they can occur at any age. Fibroids occur more often in black women than in white women. They also seem to occur at a younger age in black women and grow more quickly.
Although fibroids are quite common, little is known about what causes them.
Most fibroids, even large ones, produce no symptoms at all. When symptoms do occur, they often include:
- Changes in menstruation
- Enlarged uterus and abdomen
- Miscarriages and infertility
The first signs of fibroids may be detected during a routine pelvic exam. There are a number of tests that may show more information about fibroids:
- Hysterosalpingography (HSG)
Imaging tests, such as magnetic resonance imaging (MRI) and computed tomography (CT) scans, may be used but are rarely needed.
Although most fibroids do not cause problems, there can be complications. Fibroids that are attached to the uterus by a stem may twist. This can cause pain, nausea or fever. Fibroids may become infected. In most cases, this happens only when there is an infection already in the area. In very rare cases, rapid growth of the fibroid and other symptoms may signal cancer.
Fibroids that do not cause symptoms, are small, or occur in a woman nearing menopause often do not require treatment. Certain signs and symptoms, though, may signal the need for treatment:
- Heavy or painful menstrual periods
- Bleeding between periods
- Uncertainty whether the growth is a fibroid or another type of tumor, such as an ovarian tumor
- Rapid increase in growth of the fibroid
- Pelvic pain
Fibroids may be treated with surgery. Drugs, such as gonadotropin-releasing hormone (GnRH) agonists, may be used to shrink fibroids temporarily and to control bleeding to prepare for surgery. The choice of treatment depends on factors such as your own wishes and your doctor’s medical advice about the size and location of the fibroids.
Myomectomy is the surgical removal of fibroids while leaving the uterus in place. Because a woman keeps her uterus, she may still be able to have children.
Fibroids may develop again, even after the procedure. If they do, more surgery is needed in 20 percent to 40 percent of cases.
Uterine Artery Embolization
Another way to treat fibroids is called uterine artery embolization (UAE). With this procedure, the blood vessels to the uterus are blocked. This helps stop the blood flow that allows fibroids to grow.
This procedure usually is performed in a hospital by a specially trained radiologist.
Although rare, there can be some complications with UAE. Complications may include infection and uterine injury. In most women, regular menstrual periods return shortly after the procedure. In rare cases, however, menstrual periods do not resume and menopause begins. The effects of UAE on a woman’s fertility are not known.
Hysterectomy is the removal of the uterus. The ovaries may or may not be removed. It depends on other factors.
Hysterectomy may be needed if:
- Pain or abnormal bleeding persists
- Fibroids are very large
- Other treatments are not possible
Uterine Fibroids and Pregnancy
A small number of pregnant women have uterine fibroids. If you are pregnant and have fibroids, they likely won’t cause problems for you or your baby.
During pregnancy, fibroids may increase in size. Coupled with the extra demands placed on the body by pregnancy, growth of fibroids may cause discomfort, feelings of pressure, or pain. Fibroids decrease in size after pregnancy in most cases.
Uterine fibroids are benign growths that occur quite often in women. About one in four or five women older than 35 years has them. Fibroids may cause no symptoms and require no treatment.
This excerpt from ACOG’s Patient Education Pamphlet is provided for your information. It is not medical advice and should not be relied upon as a substitute for visiting your doctor. If you need medical care, have any questions, or wish to receive the full text of this Patient Education Pamphlet, please contact your obstetrician-gynecologist.
To ensure the information is current and accurate, ACOG titles are reviewed every 18 months