Fibroids

A fibroid is a noncancerous tumor composed of muscle and fibrous tissue.

Fibroids are also known as fibromyomas, fibromas, myofibromas, leiomyomas, and myomas. Fibroids in the uterus are the most common noncancerous tumor of the female reproductive tract. They occur in one fourth of white women and one half of black women.

What causes fibroids to grow in the uterus is unknown. High estrogen levels seem to stimulate their growth. Thus, fibroids often grow larger during pregnancy and shrink after menopause. If fibroids grow too large, they may not be able to get enough blood. As a result, they begin to degenerate.

Fibroids may be microscopic or as large as a basketball. They may grow in the wall of the uterus, from the wall into the interior of the uterus (sometimes from a stalk), under the lining of the uterus, or on the outside of the uterus. Usually, more than one fibroid is present. Large fibroids that grow in the wall or under the lining of the uterus can distort the shape or interior of the uterus.

Symptoms

Symptoms depend on the number of fibroids present, their size, and their location in the uterus. Many fibroids, even large ones, do not cause symptoms. However, large fibroids, particularly those that grow in the wall of the uterus, may cause pain, pressure, or a feeling of heaviness in the pelvic area during or between menstrual periods. Fibroids may press on the bladder, making a woman need to urinate more frequently or more urgently. They may press on the rectum, causing discomfort and constipation. Large fibroids may cause the abdomen to enlarge. A fibroid growing from a stalk inside the uterus may twist and cause severe pain. Fibroids that are growing or degenerating usually cause pressure or pain. Pain due to degenerating fibroids can last as long as they continue to degenerate.

Fibroids, particularly those just under the lining of the uterus, commonly cause menstrual bleeding to be heavier or to last longer than usual. Anemia may result from the loss of blood. Less often, fibroids cause bleeding between menstrual periods, after sexual intercourse, or after menopause. Rarely, fibroids cause infertility by blocking the fallopian tubes or distorting the shape of the uterus, making implantation of a fertilized egg difficult or impossible.

Fibroids that cause no symptoms before pregnancy may cause problems during pregnancy. Problems include miscarriage, early (preterm) labor, abnormal positioning (presentation) of the baby before delivery, and excessive blood loss after delivery (postpartum hemorrhage).

Rarely, cancerous tumors that resemble fibroids (sarcomas) develop in the uterus (see Section 22, Chapter 252).

Diagnosis

Doctors can often detect fibroids during a pelvic examination. Several procedures that enable doctors to examine the uterus can confirm the diagnosis. For transvaginal ultrasonography, an ultrasound device is inserted into the vagina. For saline infusion sonohysterography, ultrasonography is performed after a small amount of fluid is infused into the uterus to outline its interior. For hysteroscopy, a flexible viewing tube is inserted through the vagina and cervix into the uterus. A local, regional, or general anesthetic is used. Sometimes magnetic resonance imaging (MRI) or computed tomography (CT) is also performed. Additional tests are usually unnecessary.

If bleeding (other than menstrual) has occurred, doctors may want to exclude cancer of the uterus. So they may perform a Papanicolaou (Pap) test, biopsy of the uterine lining (endometrial biopsy), ultrasonography, sonohysterography, or hysteroscopy.

Treatment

For most women who have fibroids but no symptoms, treatment is not required. They are reexamined every 6 to 12 months to determine whether the fibroid is growing.

Several treatment options, including drugs and surgery, are available if bleeding or other symptoms worsen or if fibroids enlarge substantially.

Drugs: Drugs may be used to relieve symptoms or to shrink fibroids, but only temporarily. No drug can permanently shrink a fibroid. Nonsteroidal anti-inflammatory drugs (NSAIDs), alone or given with a progestin (a drug similar to the hormone progesterone), can reduce bleeding caused by fibroids. Both are usually taken by mouth, but the progestin may be injected into muscle. Danazol (a synthetic hormone related to testosterone) can suppress the growth of a fibroid, but it is rarely used because of its side effects (see Section 22, Chapter 245). Hormonal contraceptives (see Section 22, Chapter 246) can control bleeding in some women. However, when women discontinue contraceptives, abnormal bleeding and pain tend to recur. Also, when some women are treated with contraceptives, the fibroids grow.

Synthetic forms of gonadotropin-releasing hormone (GnRH agonists) can shrink fibroids and reduce bleeding by causing the body to produce less estrogen (and progesterone). GnRH agonists may be given before surgery to make removal of fibroids easier. They are injected once a month, used as a nasal spray, or implanted as a pellet under the skin. They can be given only for a few months, because if taken for a long time, they may cause a decrease in bone density and increase the risk of osteoporosis (see Section 22, Chapter 245). Estrogen may be given in low doses with GnRH agonists to help prevent side effects. Fibroids often regrow within 6 months after the GnRH agonist is discontinued.

Surgery: Surgery may involve removal of the fibroids (myomectomy) or removal of the entire uterus (hysterectomy). In contrast with hysterectomy, myomectomy usually preserves the ability to have children and avoids the psychologic effects of removing the uterus. However, fibroids regrow in up to 50% of women.

For myomectomy, an incision may be made in the abdomen. Or a viewing tube with surgical attachments may be inserted through a small incision just below the navel (laparoscopy) or through the vagina into the uterus (hysteroscopy). Which method is used depends on the size, number, and location of fibroids. Laparoscopy and hysteroscopy are outpatient procedures, and recovery is faster than recovery after an abdominal incision. However, laparoscopy often cannot be used to remove large fibroids, and the risk of complications after laparoscopy can be higher.

Hysterectomy is usually considered when symptoms, such as pain and bleeding, are severe enough to interfere with daily activities and other treatments have been ineffective. If a woman is bothered by large fibroids that she can feel, she may choose to have a hysterectomy. Hysterectomy is performed only in women who do not wish to become pregnant. It is the only permanent solution to fibroids. For treatment of fibroids, only the uterus is removed, not the ovaries.

Other Treatments: New procedures that destroy rather than remove fibroids appear to shrink fibroids. In myolysis, a needle that transmits an electrical current is inserted into the fibroid during laparoscopy. The current is used to destroy the core of the fibroid, causing the fibroid to shrink. In cryomyolysis, a similar procedure, a cold probe (containing liquid nitrogen) is used to destroy the core of the fibroid. Whether these procedures affect the ability to become pregnant is unknown. Also, fibroids tend to grow back after these procedures.

In uterine artery embolization, a thin tubular, flexible instrument (catheter) is inserted into the main artery of the thigh (femoral artery) through a puncture made with a needle or through a tiny incision. Before the procedure, a local anesthetic is given to numb the insertion site. The catheter is threaded to the artery that supplies the fibroid. Small synthetic particles are injected. They travel to the small arteries supplying the fibroid. There, they block blood flow, causing the fibroid to shrink. Whether the fibroid will regrow (because blocked arteries reopen or new arteries form) and whether the woman can become pregnant are unknown. The most common problems after this procedure are pain and infection.

After these procedures, fibroids may grow back, or if they could not be completely removed, they may continue to grow. In such cases, a woman may need to have a hysterectomy.