Although the exact cause is unknown, the growth of fibroids seems to be related to a gene that controls cell growth. When this gene functions normally, cells grow normally. When the gene is not functioning, cells grow and divide at an accelerated rate. Fibroid growth is affected by the reproductive hormones estrogen and progesterone. When these hormone levels decrease at menopause, many of the symptoms of fibroids begin to resolve.
Women with one or more pregnancies that extended beyond 5 months have a decreased risk of fibroid formation.
Use of birth control pills can generally protect against fibroids, but use of the pill at an early age (between age 13 and 16) may be associated with an increased risk.
Women who smoke appear to have a decreased risk of having fibroids. This may be due to the estrogen-lowering effect of smoking.
Eating large amounts of red meats is associated with an increased risk, and consumption of green vegetables decreases risk.
Fibroids may cause the menstrual bleeding to be heavier, increase in the duration of bleeding, or cause bleeding in between periods. The presence and degree of uterine bleeding is determined mainly by the location of the fibroid.
Larger fibroids may cause a sense of pressure and fullness in the abdomen, similar to that caused by pregnancy. If the fibroid is pressing on the bladder, frequent urination can occur. A fibroid that pushes on the rectum can cause constipation, and one that puts pressure on the cervix can result in painful intercourse.
A large fibroid may distort the pelvic anatomy sufficiently to make it difficult for the fallopian tube to capture an egg at the time of ovulation. Fibroids in the muscle portion of the uterus may cause an alteration or reduction of blood flow to the uterine lining, making it more difficult for an implanted embryo to grow and develop.
There is a slightly increased risk of certain problems during pregnancy in women with very large fibroids, including difficulties with labor, breech presentation of the fetus, premature rupture of the “bag of waters”, and abruptio placenta. However, many women with fibroids have completely normal pregnancies and deliver healthy babies with no complications.
Larger fibroids, especially those that protrude on the outside of the uterus, may be felt during a routine pelvic exam. However, in an infertility center, most fibroids are detected by ultrasound.
Ultrasound is able to detect much smaller fibroids than those that can be appreciated by a pelvic exam. It can also determine the exact number, size, and location of the fibroids with respect to the uterine cavity.
This procedure uses clear dye that shows up on x-ray film to separate the walls of the uterine cavity. It can detect intracavitary fibroids as filling defects inside the uterine cavity. It also determines whether the fallopian tubes are blocked.
A fiberoptic telescope is inserted through the vagina and cervix into the uterus. This can detect fibroids within the uterine cavity or those causing significant distortion of the cavity. At the same time, fibroids can be resected using a resectoscope.
MRI uses high-powered magnets to differentiate between fibroid tissue and normal uterine tissue. It is also helpful in distinguishing between fibroids and a condition known as adenomyosis.
Fibroids may also be identified during abdominal surgery such as laparoscopy, which is useful for fibroids that distort the outer contour of the uterus or those attached to the uterus by a thin stalk.
If there are no symptoms, treatment may not be necessary. For women with significant symptoms, medications such as gonadotropin-releasing hormone (GnRH) analogs are commonly used. They can temporarily shrink fibroids and help manage heavy bleeding before surgery.
The type of surgery required depends on the size, number, and location of the fibroids. Women who want to preserve fertility may undergo the following procedures:
While serious complications are rare, they can include bleeding, infection, or injury to surrounding structures. Additionally, a hysterectomy may be required in extreme cases. About 11-26% of women who undergo myomectomy may need a second surgery, and there is a small risk of uterine rupture during pregnancy or labor, leading to a recommendation for cesarean delivery.
There is ongoing debate about whether or not fibroids should be removed in cases of infertility. Fibroids that distort the uterine cavity or protrude into the cavity are generally considered for removal, but small fibroids within the muscular wall of the uterus remain a controversial subject in infertility treatment.
