Complications:

Effect on Fertility

The effect of fibroids on fertility is controversial and considered the source of infertility only in a very small percentage of women with this problem. Large fibroids may cause infertility by:

• Impairing the uterine lining
• Blocking the fallopian tubes
• Distorting the shape of the uterine cavity
• Altering the position of the cervix and preventing sperm from reaching the uterus

Some evidence suggests that even small fibroids may reduce the chances of pregnancy in women who are undergoing assisted reproductive techniques. Treatments to reduce fibroids may be helpful in such women, although there has been little research on this subject.

Effect on Pregnancy

Fibroids can increase pregnancy complications and delivery risks. These include:

• Cesarean section delivery
• Breech presentation (baby enters the birth canal upside down with feet or buttocks emerging first)
• Preterm birth
• Placenta previa (placenta covers the cervix)
• Excessive bleeding after giving birth (postpartum hemorrhage)

Anemia

Anemia due to iron deficiency can develop if fibroids cause excessive bleeding. Oddly enough, smaller fibroids, usually submucous, are more likely to cause abnormally heavy bleeding than larger ones.

Most cases of anemia are mild. Mild anemia can cause weakness and fatigue. Moderate-to-severe anemia can cause shortness of breath, rapid heart rate, lightheadedness, headaches, ringing in the ears (tinnitus), irritability, pale skin, restless legs syndrome, and mental confusion. Heart problems can occur if prolonged and severe anemia is not treated. Pregnant women who are anemic, particularly in the first trimester, have an increased risk for pregnancy problems.

Urinary Tract Infection

Large fibroids that press against the bladder occasionally result in urinary tract infections. Pressure on the ureters may cause urinary obstruction and kidney damage.

The female and male urinary tracts are relatively the same except for the length of the urethra.

Severe Pain

Fibroids can cause cramping during a period, which can be quite intense at times.

Pain can also develop if the blood supply is cut off from the fibroid tissue. In such cases, the cells blacken and die (a process called necrosis) from lack of oxygen. This event may occur under the following circumstances:

• A very large fibroid outgrows its own blood supply.
• A pedunculated fibroid (one that grows on a stem from the uterine wall) becomes twisted, thus cutting off its blood supply.
• Pregnancy occurs, in which the risk for fibroid cell degeneration and necrosis increases.

Leiomyomas that Spread Outside the Organ

Rarely, a fibroid breaks away from the uterus and develops in other locations. They are typically one of the following:

• Benign Metastasizing Leiomyoma, or BML (which usually spreads to the lung)
• Disseminated Peritoneal Leiomyomatosis (which spreads to the abdominal wall)

Neither is cancerous, although there is some evidence that BML, which often occurs after menopause, may represent a slow-growing variant of leiomyosarcoma.

Uterine Cancer

Fibroids are nearly always noncancerous, even if they have abnormal cell shapes. Cancer of the uterus nearly always develops in the lining of the uterus (endometrial cancer). Only in rare cases (fewer than 0.1%) does cancer develop from a malignant change in a fibroid (called leiomyosarcoma). Nevertheless, rapidly enlarging fibroids in a premenopausal woman or even slowly enlarging fibroids in a postmenopausal woman need evaluation to rule out cancer.