A fibroid tumor, also called a leiomyoma or myoma, is a benign mass of compacted muscle and fibrous tissue that grows in, on, or outside a woman’s uterus. A woman may have one or a cluster of several fibroids of varying sizes – as small as a pea or as large as a small melon. According to the U.S. National Institutes of Health, at least 25 percent of women develop fibroids.
Fibroids usually develop before pregnancy; however, because many women experience no symptoms, they may not realize they have them until they have an ultrasound during their pregnancy. However, in some women fibroids can cause heavy bleeding or painful periods, bleeding between periods, a feeling of fullness in the lower abdomen, frequent urination, painful sex, lower back pain, and reproductive problems such as infertility, miscarriage, or preterm labor.
Fibroids do not increase the risk of uterine cancer, and experts do not know specifically what causes fibroids to begin growing, but they believe estrogen plays a role. The tumors tend to grow if you are taking birth control pills containing estrogen, and during pregnancy when more hormones are released. They also tend to shrink or disappear completely after menopause.
Many women experience no pregnancy complications due to their fibroids; however, the nature of the tumors may change during pregnancy. Most fibroids increase in size, probably due to increased blood flow to the uterus and the increase in estrogen. In some women, however, the fibroids actually shrink during pregnancy, for reasons that are not well understood. Fibroids cause light vaginal bleeding and abdominal pain in approximately 10 to 30 percent of pregnant women, but unless the bleeding is substantial, the baby is usually not affected. The major concerns with fibroids during pregnancy are preterm labor, placental abruption, and restricted fetal growth. The fibroids can disrupt normal development and expansion of the womb, leading to premature birth (although usually only 2 to 3 weeks early, which is of little threat to the baby). They may also affect how a fertilized egg implants in the uterus, which can lead to miscarriage. If the placenta develops over a fibroid, there is an increased risk of the placental abruption. Depending on their size, they may also stall birth, cause the baby to be in an abnormal position for birth, or block the baby’s passage if they are located in or near the cervical opening. All of these problems may increase the likelihood of a cesarean delivery.
Fibroids are more common in women in their 40s and 50s, in African-American women (who tend to get them at a younger age), and women who are overweight or obese. Women who have previously given birth are slightly less likely to develop fibroids. There are four types of fibroids, classified depending on their location in the uterus:
Subserosal fibroids develop in the outer portion of the uterus and continue to grow outward. These usually do not affect a woman’s menstrual flow, but can cause pain depending on their size and if they put pressure on surrounding organs.
Intramural fibroids are the most common and develop within the uterine wall, which makes the uterus feel and appear larger than normal. This type of fibroid can cause heavy menstrual flow, pelvic pain, back pain, frequent urination, and pressure.
Submucosal fibroids are the least common type of fibroid and develop just under the lining of the uterine cavity. They can cause heavy and prolonged menstrual periods.
Pedunculated fibroids grow on a stalk in the uterus or on the outside of the uterus.
Your doctor can confirm you have fibroids by performing an ultrasound, MRI, x-ray, or a CT scan. You and your doctor can determine an appropriate treatment based on several factors, including if you are experiencing any negative symptoms due to the fibroids; if you are pregnant, or wish to be in the future; the size and location of the fibroids; and your age. In many cases, if you have no symptoms, you will not need any treatment. However, your doctor will continue to monitor the fibroids to check for growth or change.
If your fibroids cause moderate or severe symptoms, drugs or surgery can be used to remove or shrink them. Gonadotropin releasing hormone agonists, or GnRHa, is used to shrink the fibroids. It stops the ovaries from producing hormones, which causes a “medical menopause” and normal menopausal symptoms such as hot flashes, decreased sex drive, depression, insomnia, and joint pain. Another drug option is an anti-hormonal agent, such as mifepristone, which can stop or slow the growth of fibroids. However, they provide only a temporary relief; once you stop the treatment, the fibroids often grow back.
One surgical method of dealing with fibroids is a myomectomy, which removes the fibroids without taking the healthy uterine tissue. It can be performed either through an abdominal incision or vaginally. This is the preferred method if you are planning to have children in the future; however it is considered more dangerous than a hysterectomy. An endometrial ablation destroys the uterine lining. This method controls heavy bleeding, but you cannot have children afterwards. Myolysis involves inserting an electrical needle into the uterus through a small incision in the abdomen to destroy the blood vessels that feed the fibroids. A hysterectomy is the removal of the entire uterus and is the only way to permanently cure uterine fibroids. This method is recommended for women who have large fibroids or experience heavy bleeding and are near or past menopause, or do not want children.
Uterine Fibroid Embolization, or UFE, is a minimally invasive method of blocking the arteries that supply blood to the fibroids. A catheter is inserted into the arteries that supply the fibroids with blood, and small particles are then injected to block the flow of blood and essentially starve the fibroids. There is a small, but definite, risk that UFE will cause early menopause.
One of the newest treatments is MRI-guided ultrasound. It uses MRI images to plan and guide focused ultrasound waves that destroy fibroid tissue. The procedure is non-invasive and can be done as an outpatient procedure.
If a fibroid outgrows its blood supply, it may undergo “red degeneration” when it bleeds into itself. This often happens during the second trimester of pregnancy and can be extremely painful, but usually resolves itself without requiring treatment. A fibroid may also undergo “white degeneration,” when portions undergo cell death and liquefy or develop into a cyst. This can also cause pelvic and/or abdominal pain.