Uterine fibroids are noncancerous (benign) tumors that develop in the uterus (womb), a female reproductive organ.
Leiomyoma; Fibromyoma; Myoma; Fibroids
Causes, incidence, and risk factors
Uterine fibroids are the most common pelvic tumor. As many as 1 in 5 women may have fibroids during their childbearing years (the time after starting menstruation for the first time and before menopause).
Fibroids usually affect women over age 30. They are rare in women under 20, and often shrink and cause no symptoms in women who have gone through menopause. They are more common in African Americans than Caucasians.
The cause of uterine fibroid tumors is unknown. However, fibroid growth seems to depend on the hormone estrogen. As long as a woman with fibroids is menstruating, a fibroid will probably continue to grow, usually slowly.
Fibroids can be so tiny that you need a microscope to see them. However, they can grow very large. They may fill the entire uterus, and may weigh several pounds. Although it is possible for just one fibroid to develop, usually there are more than one.
Fibroids are often described by their location in the uterus:
- Myometrial -- in the muscle wall of the uterus
- Submucosal -- just under the surface of the uterine lining
- Subserosal -- just under the outside covering of the uterus
- Pendunculated -- occurring on a long stalk on the outside of the uterus or inside the cavity of the uterus
More common symptoms of uterine fibroids are:
- Abdominal fullness, gas, or constipation
- Bleeding between periods
- Increase in urinary frequency
- Heavy menstrual bleeding (menorrhagia), sometimes with the passage of blood clots
- Menstrual periods that may last longer than normal
- Pelvic cramping or pain with periods
- Sensation of fullness or pressure in lower abdomen
- Pain during intercourse
Note: There are often no symptoms.
Signs and tests
A pelvic examination may show an irregularly shaped, lumpy, or enlarged uterus. Frequently, this diagnosis is reliable. In some cases, it is difficult to diagnose fibroids, especially in obese women. Fibroid tumors have been mistaken for:
- Ovarian tumors
- Inflammation of the fallopian tubes
- Uterine adenomyosis (a condition in which the uterine lining grows into the muscle wall of the uterus)
A transvaginal ultrasound or pelvic ultrasound may be done to confirm the diagnosis of fibroids. Sometimes, a pelvic MRI is used to confirm the diagnosis.
An endometrial biopsy (biopsy of the uterine lining) or laparoscopy may be needed to rule out cancer.
Treatment depends on various factors, including:
- General health
- Severity of symptoms
- Type of fibroids
- Whether you are pregnant
- If you want children in the future
Some women may just need pelvic exams or ultrasounds every once in a while to monitor the fibroid's growth.
Treatment for the symptoms of fibroids may include:
- Birth control pills (oral contraceptives) to help control heavy periods
- Intrauterine devices (IUDs) that release the hormone progestin to help reduce heavy bleeding and pain
- Iron supplements to prevent or treat anemia due to heavy periods
- Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or naprosyn for cramps or pain
Hormonal therapy (gonadotropin releasing hormone (GnRH) agonists or Depo Leuprolide injections) may be used to help shrink the fibroids. This therapy is used only for a short period of time, either before surgery to remove a fibroid or when a woman is expected to reach menopause soon. Side effects include hot flashes and vaginal dryness.
Surgery and procedures used to treat fibroids include:
- Hysteroscopic resection of fibroids: Women who have fibroids growing inside the uterine cavity may need this outpatient procedure. In this procedure, a small camera and instruments are inserted through the cervix into the uterus to remove the fibroid tumors.
- Uterine artery embolization: This procedure stops the blood supply to the fibroid, causing it to die and shrink. Uterine artery embolization is not used to treat large fibroids. Women who may want to become pregnant in the future should discuss this procedure with their health care provider.
- Myomectomy: This surgery removes the fibroids. It is often the chosen treatment for women who want to have children, because it usually can preserve fertility. Another advantage of a myomectomy is that it controls pain or excessive bleeding that occurs in some women with uterine fibroids. More fibroids can develop after a myomectomy.
- Hysterectomy: This invasive surgery may be an option if medicines do not work and other surgeries and procedures are not an option.
National Uterine Fibroid Foundation - www.nuff.org
Some women with fibroids have no symptoms and may not need treatment.
During a pregnancy, existing fibroids may grow due to the increased blood flow and estrogen levels. The fibroids usually return to their original size after the baby is delivered.
Fibroids may cause pregnancy complications, although the risk is thought to be small:
- Most women are able to carry their babies to term, but some end up delivering prematurely because there is not enough room in the uterus.
- Some pregnant women with fibroids may need a cesarean section because fibroids can occasionally block the birth canal or cause the baby to be positioned wrong.
- Some pregnant women with fibroids have heavy bleeding immediately after giving birth.
Other complications of fibroids include:
- Severe pain or excessively heavy bleeding that may require emergency surgery
- A pedunculated fibroid can become twisted and cause a kink in the blood vessels feeding the tumor (this type of fibroid may need surgery)
- Anemia (which may be severe if the bleeding is very heavy)
- Urinary tract infections, if pressure from the fibroid prevents the bladder from fully emptying
- Cancerous changes called leiomyosarcoma (in rare cases)
- Infertility (rarely)
Calling your health care provider
Call your health care provider if:
- You have gradual changes in your menstrual pattern, including a heavier flow, increased cramping, or bleeding between periods
- Fullness or heaviness develops in your lower abdomen
Katz VL. Benign gynecologic lesions: Vulva, vagina, cervix, uterus, oviduct, ovary. In: Katz VL, Lentz GM, Lobo RA, Gershenson DM, eds. Comprehensive Gynecology. 5th ed. Philadelphia, Pa: Mosby Elsevier; 2007:chap 18.
Viswanathan M, Hartmann K, et al. Management of uterine fibroids: an update of the evidence. Evid Rep Technol Assess. 2007;154:1-122.
Van Voorhis B. A 41-year-old woman with menorrhagia, anemia, and fibroids: review of treatment of uterine fibroids. JAMA. 2009;301:82-93.
American College of Obstetricians and Gynecologists. ACOG practice bulletin. Alternatives to hysterectomy in the management of leiomyomas. Obstet Gynecol. 2008;112:387-400.
A.D.A.M. Editorial Team: David Zieve, MD, MHA, and David R. Eltz. Previously reviewed by Susan Storck, MD, FACOG, Chief, Eastside Department of Obstetrics and Gynecology, Group Health Cooperative of Puget Sound, Redmond, Washington; Clinical Teaching Faculty, Department of Obstetrics and Gynecology, University of Washington School of Medicine (9/2/2009).
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