Fibroids are the most common tumors in the female reproductive system. They increase with age and as many as 50% of women at age 50 have one or more fibroids. They are the most common cause for hysterectomy. While fibroids are common in all races, studies have shown that they are more common in African-Americans.

What are fibroids?

Uterine fibroids, also called myomas or leiomyomas, are a benign tumor of the muscle of the uterus. Fibroids may range from the size of a pea to that of a basketball. They may be single or multiple.

Fibroids are usually described by the position they occupy in the uterus. Some fibroids may be connected to the uterus only by a thin stalk. These are called pedunculated fibroids and are the least symptomatic of all types of fibroids. If the fibroid is on the outside of the uterus, it is called subserosal. Subserosal fibroids usually cause fewer problems than those located deeper in the uterine wall, which are called intramural. The last type of fibroid, and perhaps the most significant for abnormal bleeding and fertility, are the submucosal fibroids. These fibroids lie just under the endometrium and have an “iceberg” effect—more actually there than is exposed at the surface.

What makes them form and grow?

A fibroid forms from a single muscle cell that begins to multiply. The exact stimulus that causes this growth, or the stimulus that limits fibroid growth, is not known. While the cells of the fibroid multiply and the fibroid grows, it is very different from a cancer in that the fibroid does not invade surrounding tissues; it just pushes on them. Luckily, fibroids are universally benign, although malignant transformation is not impossible.

It is clear that fibroids are under the control of estrogen and progesterone. After menopause, when the estrogen levels fall, fibroids decrease in size. During pregnancy, fibroids often increase in size. Some fibroids grow very quickly and undergo death (degeneration) of the middle portions, thus causing pain. Degeneration of fibroids is more common during pregnancy.

How do I know I have them?

Patients with fibroids most often are seen in their gynecologist’s office with abnormal pain, abnormal uterine bleeding and enlargement of the uterus. Back pain, frequent urination, and alteration in bowel function are common symptoms. Often the fibroids are suspected by pelvic examination and can be readily confirmed by ultrasound scans. Sometimes they are discovered during an infertility evaluation.

Usually an ultrasound scan is all that is necessary to make the diagnosis. Most often fibroids have a characteristic finding by ultrasound of what is called the homogeneous echo of the “ball of muscle cells” surrounded by a capsule. While most fibroids have a uniform appearance, some older fibroids will have bright ultrasound shadows, suggesting calcification. This is a normal and benign finding. A problem that may initially look similar to a fibroid on ultrasound is an adenomyoma, which is an area of endometriosis within the muscle of the uterus. If the fibroid is near the uterine lining (submucosal) it may be difficult to distinguish from an endometrial polyp, but both of these are treated in the same way as fibroids.

How big is big? When to remove?

“Big” is always a relative term colored by the degree of discomfort caused and fears of both the patient and physician. When it is agreed that a fibroid is large and it has become unmanageable in other ways, it’s time for surgery. If pregnancy is not desired this may mean a hysterectomy. Most who have had hysterectomies because of fibroids are much improved. Bleeding is gone and other symptoms at least improved. The decision for hysterectomy is based on the size of the fibroid, how fast it is growing, the amount of problems it is causing and the desire for future pregnancy.

Unfortunately, there have been only a few studies that have specifically addressed the role of fibroids in fertility. Most believe that the fibroid must be above 3 cm. in size to have a deleterious effect on fertility. Obviously, the position of the fibroid may be more important than its size. If it is found by evaluation using hysteroscopy, hysterosalpinography, or sono-hystersalpinography that the fibroid is not impinging on the uterine cavity, therapy may not be necessary. Large fibroids, however, can further enlarge and cause pain in early pregnancy, possibly altering the implantation site and causing early or obstructed labor. A fibroid in the wall of the uterus may prevent the uterus from properly expanding in pregnancy, or stimulate premature contractions.

There is probably adequate justification for removing all fibroids greater than 6 cm. regardless of their position.

How are fibroids removed?

Submucosal fibroids are usually removed by hysteroscopy. Intramural and subserosal fibroids are removed by a procedure called myomectomy, which can be performed either through an abdominal incision (laparotomy) or by “band aid surgery” (laparoscopy.) Some surgeons believe that any fibroid which is sufficiently easy to remove at laparoscopy may be insignificant in its capacity to effect fertility. Certainly, the laparoscopic procedure has a much shorter recovery time, but the decision for laparoscopic removal should be carefully considered. There are recent studies advocating a destruction of the fibroid by an electric current without actually removing the fibroid. This procedure is questionable when a pregnancy is desired. It is not known whether this technique will abnormally weaken the wall of the uterus.

Once the fibroid is removed, the surrounding muscle is usually closed with sutures. Inside the body, the area where the fibroid has been removed forms a scar. This scar may not expand as well as the muscle during pregnancy and can result in a uterine rupture. Every patient who has had a fibroid removed should also be informed as to whether cesarean section should be performed to delivery subsequently conceived babies. Certainly, the obstetrician should be made aware of a previous myomectomy.

Are there therapies other than surgery?

Since fibroids are under the control of ovarian hormones, agents that suppress ovarian functions such as the GnRH analogs will also cause suppression of fibroids. Unfortunately, even though the suppression may reduce the fibroid size by 50%, the fibroid will quickly return when the suppressive therapy has been stopped. Sometimes pretreatment with GnRH analogs will control bleeding and will allow surgery to be carried out with less blood loss and in some cases this will allow an easier procedure. Pretreatment with GnRH analogs is especially important with hysteroscopic removal of larger fibroids. Unfortunately, suppressive therapy that lessens bleeding also increases scarring around the fibroid, thus making the removal more difficult. The effect of oral contraceptives and progestins such as Provera™ on fibroid growth is unclear. Overall, it is believed that women who use birth control pills have a lower incidence of fibroid changes.

A procedure for treating fibroids that is gaining acceptance is uterine artery embolism. In this procedure, under X-ray guidance the main blood supply to the fibroid is disrupted, causing it to shrink. It is unclear whether this technique can be safely used for those desiring a future pregnancy. Early studies have shown embolization may be associated with less favorable pregnancy outcome. It may weaken the uterine wall, or more importantly, it may alter the necessary blood supply to the uterus that is needed for normal placental function. At the same time this procedure avoids a surgical scar in the uterus, and mays lessen the chance of uterine rupture.

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