Uterine fibroids are tumors that are not cancerous that grow on or in the muscles of the uterus (womb). They are sometimes called myoma, leiomyoma, leiomyomata and fibromyoma. All women are at risk of developing fibroids at some point in their lives. They are the most common tumor of the female reproductive system.
Fibroids can range from the size of a walnut to the size of a cantaloupe or even larger. Doctors measure the size of fibroids in relationship to the size of uterus during pregnancy. A large fibroid tumor, for example, might cause the uterus to become the size of a six- or seven-month pregnancy. Fibroids can appear as a single large tumor or as a cluster of small ones.
- Subserosal fibroids develop in the outer portion of the uterus and grow outward. These fibroids can be painful if they are large and press on other organs. They usually don't affect a woman's menstrual flow.
- Submucosal fibroids develop just under the lining of the uterine cavity. These are the least common type of fibroid tumor. They often cause very heavy, long menstrual periods.
- Pedunculated uterine fibroids occur when the fibroid grows on a stalk. These can grow into the uterus or on the outside of the uterus.
A woman may have one or all of these types of fibroids. It is common that if a woman has one fibroid, she has others that have not yet been detected yet.
Symptoms of Uterine Fibroids
Some women experience no symptoms. Women sometimes underestimate the impact of their symptoms because they have gotten used to the excessive bleeding, pain and the pressure that fibroids can cause. When there are symptoms, they vary depending on the location and size of the fibroid tumors.
Common symptoms of fibroids include:
- An enlarged abdomen, which may be mistaken for weight gain or pregnancy
- Anemia from heavy menstrual bleeding, which lowers the red blood cell count. This causes a woman to feel constantly tired.
- Heavy menstrual bleeding (sometimes with clots) and long monthly periods
- Pain during sex
- Pain in the back of the legs
- Pelvic pain or pressure
- Pressure on the bladder. This causes a constant feeling of needing to urinate or make it hard to control urination.
- Pressure on the bowel. This can lead to constipation or bloating or both
Fibroid tumors are sensitive to changes in a woman's monthly hormone cycle. As estrogen levels tend to increase before menopause starts, many uterine fibroids start to grow. This may make the symptoms worse. After menopause, estrogen falls dramatically. This causes the fibroids to shrink (although they probably won't totally disappear) and the symptoms to diminish. If a woman is taking hormone replacement therapy (HRT), however, she will probably not experience a shrinking of the fibroids or a lessening of the symptoms.
Causes and Risk Factors for Uterine Fibroids
Between two and four women out of every 10 who are 35 years of age or older have fibroid tumors.
Several studies have indicated that African-American women are more likely to have fibroids than women of other origins. Also, African-American women develop symptoms faster and with greater severity than other women. Some studies suggest that up to eight out of 10 African-American women will eventually develop uterine fibroids.
Diagnosing Uterine Fibroid Tumors
If you have symptoms of fibroid tumors, you should see your doctor. For women who do not experience symptoms, uterine fibroid tumors may first be discovered at their annual gynecological exam.
The doctor will check the size of uterus during this exam. If it feels enlarged, he or she may order diagnostic tests including:
- An ultrasound of the abdomen or the vagina. An ultrasound bounces sound waves off the inside of the body to create an image of the inside of the body.
- Magnetic resonance imaging (MRI)
- Tests to rule out other, more serious conditions, such as cancers, that may have symptoms similar to fibroids.
- Tests to see if other conditions that sometimes occur with fibroids are present. These conditions include adenomyosis (components normally in the endometrium are within the myometrium) and endometriosis (endometrial tissue is generally found outside of the uterus).
Treating Fibroid Tumors
If you are diagnosed with fibroids, your doctor will discuss treatment options with you. The treatment that he or she recommends will depend on a variety of factors including the size of the fibroids, how severe the symptoms are and how much they affect your daily life.
Treatment of fibroid tumors may consist of any or a combination of:
- Watchful waiting. If your fibroids don't cause symptoms, treatment isn't needed. Your doctor may want to check the fibroids at each of your annual gynecological exams to make sure they aren't growing.
- Hormonal treatments (such as birth control pills) may help control excessive menstrual bleeding caused by fibroids in some patients. However, there are possible side effects, including high blood pressure, blood clots and higher risks of heart or liver disease. Studies suggest that fibroids will come back after treatment ends.
- Taking GnRH agonists, which lower how much estrogen a woman's ovaries produce. This may shrink the fibroids and help control the symptoms. GnRH agonist's effectiveness usually plateaus at three months and are often used preoperatively. GnRH agonists are prescribed when birth control pills don't control the symptoms of fibroids. However, lowering the amount of estrogen the body produces can also cause hot flashes or mood swings. There may be bone loss if GnRH agonists are used for a long time. Studies suggest that the fibroids will come back after treatment ends.
- Uterus sparing, minimally invasive procedures such as uterine fibroid embolization
- Surgery to remove the fibroids (myomectomy). While this avoids removing the womb, it can be a challenging procedure. Only certain fibroids can be treated this way.
- Surgery to remove the womb (and sometimes the fallopian tubes, ovaries and cervix). This is called a hysterectomy. After this surgery, a woman no longer has periods or is able to conceive a child. If the ovaries are removed, a woman will go through menopause, no matter how old she is.