Uterine fibroids are benign tumors that originate in the uterus (womb). Although they are composed of the same smooth muscle fibers as the uterine wall (myometrium), they are many times denser than normal myometrium. Uterine fibroids are usually round or semi-round in shape.
We do not know exactly why women develop these tumors. Genetic abnormalities, alterations in growth factor (proteins formed in the body that direct the rate and extent of cell proliferation) expression, abnormalities in the vascular (blood vessel) system, and tissue response to injury have all been suggested to play a role in the development of fibroids.
Family history is a key factor, since there is often a history of fibroids developing in women of the same family. Race also appears to play a role. Women of African descent are two to three times more likely to develop fibroids than women of other races. Women of African ancestry also develop fibroids at a younger age and may have symptoms from fibroids in their 20s, in contrast to Caucasian women with fibroids, in whom symptoms typically occur during the 30s and 40s. Pregnancy and taking oral contraceptives both decrease the likelihood that fibroids will develop. Estrogen can stimulate the growth of fibroids in some cases. In general, fibroids tend to shrink after menopause, but postmenopausal hormone therapy may cause symptoms to persist.
Overall, these tumors are fairly common and occur in up to 50% of all women. Most of the time, uterine fibroids do not cause symptoms or problems, and a woman with a fibroid is usually unaware of its presence.
Most women with uterine fibroids have no symptoms. However, abnormal uterine bleeding is the most common symptom of a fibroid. If the tumors are near the uterine lining, or interfere with the blood flow to the lining, they can cause heavy periods, painful periods, prolonged periods or spotting between menses. Women with excessive bleeding due to fibroids may develop iron deficiency anemia. Uterine fibroids that are deteriorating can sometimes cause severe, localized pain.
Fibroids can also cause a number of symptoms depending on their size, location within the uterus, and how close they are to adjacent pelvic organs. Large fibroids can cause:
pressure, pelvic pain, pressure on the bladder with frequent or even obstructed urination, and pressure on the rectum with pain during defecation.
While fibroids do not interfere with ovulation, some studies suggest that they may impair fertility.
There are many ways of managing uterine fibroids. Surgical methods are the mainstay of treatment when treatment is necessary. Possible surgical interventions include hysterectomy, or removal of the uterus (and the fibroids with it). Myomectomy is the selective removal of just the fibroids within the uterus. Myomectomy can be done through a laparoscope, robotically or with the standard abdominal incision. Surgery is necessary if there is suspicion of malignancy in any case of leiomyoma or uterine mass.
Another technique for treating fibroids is known as uterine artery embolization (UAE). This technique uses small beads which are injected through a catheter into the major arteries of the groin. The intent of the procedure is to obstruct the blood supply to the fibroid. While this technique has not been in use long enough to evaluate long-term effects of UAE versus surgery there are many reports of major complications including infection and pelvic pain.