What Are Uterine Fibroids?
Uterine fibroids are benign (noncancerous) growths of the muscular wall of the uterus. The growths, which may be solitary or multiple in number, range from the size of a pea to the size of a mass that can fill the entire abdomen and pelvis. They are the most common pelvic tumors, with an incidence of 70-80% in a woman’s lifetime. They may grow within the muscle wall of the uterus or extend into the endometrial cavity or abdominal cavity.
Fibroids often cause no symptoms, unless they grow so large that they bring pressure to bear on adjoining organs, causing pain. They may also cause increased vaginal bleeding, which may lead to anemia.
Fibroids may increase in size during pregnancy and shrink or disappear at menopause. The growths rarely become cancerous. But they can sometimes lead to miscarriage or to premature delivery of an infant, and they can also cause problems with fertility.
Who Gets Uterine Fibroids?
Uterine fibroids are extremely common; approximately 80% of women have fibroids. However, most of these women will be asymptomatic. Only about 30% of all women have fibroids large enough to be noted during a pelvic exam. Fibroids are more common in African-American women than in white women. The reason is unknown.
Abnormally heavy bleeding during menstrual periods; bleeding between periods.
Abdominal/pelvic discomfort, fullness, or pain.
Lower back pain.
Frequent urination; constipation.
Pain during sexual intercourse.
- The cause of uterine fibroids is unknown.
- Pregnancy may promote fibroid growth (but oral contraceptives do not appear to increase the risk of fibroids).
- Obesity/overweight may increase risk.
- Alcohol consumption appears to increase risk.
- Smoking decreases risk (but this is not a reason to smoke).
- There may be familial risk: If you have a mother or sister with fibroids, some evidence suggests you are at increased risk.
- Foods from sources treated with hormones, such as eggs or processed meat, may increase fibroid growth.
- A pelvic examination may reveal the presence of uterine fibroids.
- Imaging tests can confirm the diagnosis and include the following:
- Computed tomography (CT scan or CAT scan; uses x-rays from different angles to create three-dimensional images of tissues and organs).
- Magnetic resonance imaging (MRI scan; uses electromagnetic radio waves to create detailed images of tissues and organs).
- Pelvic ultrasound (uses sound waves to create images of tissues and organs); this is the most common test ordered.
- For asymptomatic fibroids, no treatment is required. When fibroids cause pain and other symptoms, medications and surgery are options.
- Iron pills can replenish the iron lost from heavier bleeding during menstrual periods.
- Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil) may help reduce menstrual cramps and bleeding associated with fibroids.
- Oral contraceptives (birth control pills) can stabilize the lining of the uterus to prevent heavy bleeding. Other forms of birth control can also be used (below).
- A hormonal intrauterine system (Mirena), placed by a doctor inside the uterus through the cervical opening, releases a progestin birth control hormone, which can help control heavy fibroid bleeding.
- A match stick-size implant containing progestin (Nexplanon/Implanon) can be placed under the skin of the arm to slowly release progestin into the bloodstream.
- An intramuscular injection of Depo-Provera—a long-acting form of progesterone—can be given every three months for the management of fibroids that cause heavy bleeding.
- Gonadotropin-releasing hormone agonists (GnRH agonists), given by injection once a month, stop the ovaries from producing hormones and decrease the size of the uterus—which can temporarily reduce fibroid size. This is typically done to make surgery for fibroids easier and less complicated.
- Dilation and curettage, or surgical scraping of uterine tissue.
- Myomectomy. This entails surgical removal of fibroids but not the surrounding tissue of the uterus. A key advantage is that it preserves future fertility.
- Endometrial ablation. The lining of the uterus is cauterized using an electrical current, which stops heavy menstrual bleeding Though this procedure significantly reduces a woman’s chances of getting pregnant, pregnancy can still occur and there is an increased risk of complications if it does occur. Therefore, birth control is recommended.
- Uterine artery embolization. This relatively new procedure is performed by an interventional radiologist, who places material in the uterine arteries to decrease blood flow to the uterus, depriving fibroids of their blood supply and thereby causing them to shrink. It’s not clear how uterine artery embolization affects the potential for pregnancy. There is some evidence it may increase the risk of miscarriage in women who do become pregnant.
- Magnetic resonance with focused ultrasound. High-frequency ultrasound waves are used to heat and destroy fibroid tissue. This procedure is only appropriate for women who do not intend to become pregnant. It cannot treat all types of fibroids.
- Hysterectomy. Surgical removal of the uterus is performed either vaginally, abdominally, or laparoscopically, which ensures a permanent solution to fibroids. It is an option if other treatments have not worked or are not appropriate. The ovaries may also be removed, though this is not necessary for treatment of fibroids.
- Women should have annual pelvic exams to aid in early detection and treatment of any abnormalities. Annual pelvic exams are especially important for women with asymptomatic fibroids so that fibroid growth may be monitored.
When To Call Your Doctor
- Call a gynecologist if you develop symptoms of uterine fibroids.
- EMERGENCY Get immediate medical attention for sharp, sudden pain in the lower abdomen.
Reviewed by Thomas Moran, M.D., obstetrician-gynecologist in private practice, Springfield, MA.