Fibroids are pale, firm masses that sometimes form in the wall of the uterus. They result from abnormal cell development. These tumors are almost always benign and can range in size from a tiny speck to large masses that can distort the uterus and nearby organs.

Uterine fibroids usually appear during the reproductive years and tend to grow slowly over time. There are three main types of fibroids: subserosal (which grow in the outer wall of the uterus), intramural (which develop in the muscular layers of the uterine wall) and submucosal (which protrude into the uterine cavity).

Sometimes a subserosal or submucosal fibroid may develop a stalk (peduncle), similar to the stem of a plant, and hang in the uterus. These fibroids are known as pedunculated, and as they enlarge they may twist on the stalks, causing severe pain and requiring emergency treatment.

The exact causes of fibroids are not understood. But research indicates that genetics, race or ethnicity, hormonal changes and obesity may be contributing factors in development. The condition also is more prevalent among African-American women. When women with uterine fibroids stop menstruating (menopause), the fibroids usually shrink or disappear altogether.

Most uterine fibroids are small and do not produce any symptoms. In many cases, women may not be aware that they have fibroids until the gynecologist discovers them during a routine pelvic examination.

If symptoms occur they are related to the number, size and location of the fibroids. Symptoms of fibroids can include menorrhagia, severe menstrual cramps and pelvic pain as well as bladder and bowel problems, such as urinary tract infections, incontinence and constipation.

Depending upon the uterine location, fibroids sometimes may interfere with the ability to get pregnant or cause miscarriage. Although fibroids do not usually cause infertility, the condition is associated with pregnancy complications including placenta previa and premature delivery.

To confirm a diagnosis of uterine fibroids and rule out other conditions, a physician will order several tests including imaging tests (e.g., ultrasound, hysteroscopy), blood tests and endometrial biopsy.

In most cases, fibroids do not require treatment. This is especially true if symptoms are not present. When symptoms are present, treatment will depend on several factors including the severity of the symptoms, the age of the patient and whether she plans to become pregnant in the future. There are several treatment options for fibroids including medications (e.g., hormonal therapy) and in some cases surgery (e.g., myomectomy, hysterectomy).

Fibroids are benign (non-cancerous) tumors that sometimes develop inside a woman’s uterus. The uterus is the hollow, muscular organ in a woman’s pelvis where a fertilized egg implants and grows during pregnancy.

Uterine fibroids are also called fibromyomas, leiomyomas or myomas. Fibroids form from the smooth muscle cells that line the wall of the uterus (myometrium). Sometimes, a single cell reproduces repeatedly until a pale, firm, rubbery growth develops that is different from normal uterine tissue.

A single fibroid can develop or multiple fibroids may form. They range in size from tiny, undetectable growths to bulky masses that can expand and distort the uterus, and rarely, the cervix.

These non-cancerous tumors commonly appear during a woman’s reproductive years and tend to grow slowly over time. Why fibroids develop is not completely understood, but it may be related to increased levels of the hormones estrogen and progesterone. For instance, fibroids tend to increase in size faster during pregnancy, when levels of estrogen increase. Uterine fibroids typically shrink or disappear after the cessation of menstruation (menopause).

According to the American Society for Reproductive Medicine (ASRM), about one out of every four women in the United States develops uterine fibroids. They occur more frequently in African Americans than Caucasians. Fibroids are rare before age 20 but can affect up to 40 percent of women over age 30, according to the National Institutes of Health.

In many cases, women are not aware that they have uterine fibroids because fibroids often do not cause symptoms. In such cases, treatment is not necessary. However, if the fibroids grow too large and/or the location compromises the health of the uterus and nearby organs, severe symptoms can develop and require medical attention.

Rarely, fibroids may interfere with a woman’s ability to conceive (infertility). Sometimes the changes that are taking place in the endometrium as a result of the fibroids may prevent the implanting of a fertilized egg to the uterine wall. Other times, the fibroids may compress or block the fallopian tubes, thereby preventing sperm from fertilizing an egg. In some cases, a large fibroid may interfere with the growth of a fetus and contribute to a miscarriage.

Although uterine fibroids usually do not cause infertility, the condition can be associated with pregnancy complications including placenta previa and early labor and premature delivery. In such cases, complications are often due to large fibroids occupying needed space in the uterus. Pregnant women with fibroids also may require a Caesarean delivery in more cases, especially if the fibroids are blocking the birth canal or causing the baby to be positioned improperly (e.g., breech).

In addition, there is a very small possibility that some fibroids may become cancerous. According to the ASRM, the risk of fibroids becoming cancerous (malignant) is about one in 1,000 in women of reproductive age. However, after menopause a fibroid that suddenly becomes larger may be cancerous (leiomyosarcoma).

Uterine fibroids often appear in clusters, although in rare instances only a single fibroid may develop. They generally form in the wall of the uterus (womb), but also may grow into the cervix. These benign tumors range in size from tiny, undetectable specks to large, bulky masses. Large fibroid masses left untreated may compromise a woman’s reproductive health.

Fibroids are classified depending on their location in the uterus:

• Intramural fibroids. These fibroids develop in the muscular layers of the uterine wall (myometrium). Intramural fibroids are the most common type of fibroids.
  
  
• Subserosal fibroids. The second most common type, subserosal fibroids grow in the outer wall of the uterus.
  
  
• Submucosal fibroids. The least common form of fibroids, they protrude into the uterine cavity.
  
  
• Pedunculated fibroids. Sometimes a subserosal or submucosal fibroid develops a stalk (peduncle), similar to the stem of a plant, and hangs from the uterus. These fibroids are known as pedunculated, and as they get bigger they may twist on their stalks, causing severe pain.
  
  
• Parasitic fibroids. A rare condition that occurs when a uterine fibroid attaches itself to another organ.

It is not uncommon for women to have more than one type of uterine fibroids.

Fibroids develop from abnormal cell growth in the uterus (womb). The exact cause of these benign tumors is not known. However, both genetic and environmental conditions have been identified as contributing risk factors for fibroids. A number of factors may increase a woman’s likelihood of developing uterine fibroids. These include:

• Age. Although they can occur at any age after puberty, fibroids most frequently appear in women aged 30 to 40 years old. In addition, early age at menarche, especially before age 10, is considered a risk factor for the condition later in life.
  
  
• Genetics and heredity. Research indicates that many fibroids contain alterations in genes that code for uterine muscle cells. Women who have a mother or sister with fibroids appear to be at increased risk of developing them.
  
  
• Ethnicity. Fibroids tend to appear more frequently among black women than Caucasians. Also, black women tend to develop fibroids at younger ages, and also typically experience numerous and/or larger fibroids.
  
  
• Hormonal changes. Research indicates that the hormones estrogen and progesterone appear to influence the growth of uterine fibroids. When a woman with uterine fibroids experiences hormonal changes during pregnancy, the fibroids typically enlarge. However, after childbirth the fibroids tend to shrink back to the original size. In addition, when women stop menstruating (menopause), uterine fibroids usually shrink or disappear altogether. Other studies indicate that hormones that help the body maintain tissues, such as the insulin-like growth factor, may also affect fibroid growth.
  
  
• High-fat diet and alcohol consumption. Significant consumption of red meats (e.g., beef, ham) and alcoholic beverages, especially beer, is associated with an increased risk of developing fibroids in the uterus.
  
  
• Obesity. Having a body mass index (BMI) of 30 or greater appears to increase a woman’s risk of developing these benign tumors of the uterus.

In addition, researchers have identified certain factors that are associated with a decreased risk of developing uterine fibroids:

• Oral contraceptives. The use of low dose birth control pills is associated with a reduced risk of developing these benign tumors. However, the use of the pill at an early age, between 13 and 16 years, is associated with an increased risk of developing uterine fibroids.
  
  
• High-vegetable diet. Eating plenty of green vegetables (e.g., spinach, broccoli) is believed to be associated with a reduced risk of fibroid formation. However,  no study has demonstrated that a change in diet influences the incidence or symptoms of fibroids.
  
  
• Smoking. Some studies indicate that women who smoke appear to have a reduced risk of developing fibroids. However, the severe health consequences associated with smoking (e.g., lung cancer) outweigh any small benefit tobacco may provide against fibroids.

Most uterine fibroids are small and do not produce any symptoms. Many women may not even be aware that they have them until their physician, usually a gynecologist, discovers them during a routine pelvic examination.

When symptoms occur, they are related to the number, size and location of the fibroids. They include:

• Abnormal uterine bleeding. Prolonged and heavy menstrual periods (menorrhagia) are often associated with large intramural and submucosal  fibroids, which can distort or enlarge the uterine cavity and create a larger surface area for bleeding. However, women with all types of fibroids can experience heavy menstrual bleeding. The cause of abnormal bleeding is not completely understood. Menorrhagia can put women at risk of developing anemia (reduced blood iron levels). Women with fibroids also may experience more severe menstrual cramps. Sometimes, fibroids may cause bleeding or spotting between periods (metrorrhagia).
  
  
• Pelvic pain or pressure. Depending on the location, large fibroids can press and/or cause pain in the pelvic organs including the uterus, ovaries, fallopian tubes, cervix, vagina, bladder or rectum. The pain also may extend to the lower back and legs. Large and bulky fibroids also may make sexual intercourse uncomfortable or painful. Pain is most frequently associated with the premenstrual period and menstruation, but in some rare cases pain may occur throughout the menstrual cycle.
  
  
• Bladder and/or bowel problems. Large fibroids that press on the bladder or ureters can cause frequent urination or difficulty urinating. Prolonged pressure on the ureters also can result in recurrent urinary tract infections, urinary incontinence and bladder or kidney infections if the fibroids are not removed. Large fibroids that are located in the lower portion of the uterus can put pressure on the large bowel and rectum, which can result in bloating and gas, painful bowel movements (dyschezia), constipation and/or hemorrhoids (swollen veins in the anus and lower rectum that may bleed).

Patients experiencing any of these symptoms should consult their physician, preferably a gynecologist, to determine the cause.

In rare cases, a fibroid can cause sudden and severe pain when it outgrows its blood supply. Deprived of blood, the tumor begins to break down (degenerate) and eventually dies. Substances from a degenerating fibroid can seep into surrounding tissue in the uterus causing severe pelvic pain accompanied by mild fever and nausea. A pedunculated fibroid, which hangs by a stalk, also may cause acute pain by turning on the stalk. This condition also is uncommon. In such instances, uterine fibroids can require emergency treatment.

Because uterine fibroids often do not produce any symptoms, many women may not be aware of them. A physician, typically a gynecologist, may discover the presence of fibroids during a routine pelvic examination or while testing for another condition. Upon palpation, the uterus may feel irregularly shaped, lumpy or enlarged. This is typically indicative of fibroids. However, a physician will usually order several diagnostic tests to rule out other disorders with symptoms similar to uterine fibroids, as well as gynecologic cancers. Other conditions that may cause similar symptoms include the following:

• Endometrial polyps. Benign (non-cancerous) tumors that grow in the lining of the uterus (endometrium). Symptoms of endometrial polyps include heavy menstrual bleeding, spotting after the menstrual period or spotting that is not related to menstruation.
  
  
• Adenomyosis. In this condition, cells that normally make up the endometrium penetrate into the muscular wall of the uterus (myometrium) and may cause symptoms, such as abnormal uterine bleeding and pelvic pain.
  
  
• Ovarian cysts. Fluid-filled structures that form within or on the ovaries. Abnormal cysts are usually benign but in rare cases may be malignant. Symptoms of ovarian cysts include painful or irregular menstrual periods. A cyst that ruptures can cause severe one-sided pelvic pain.
  
  
• Hormonal imbalance. Hormones are responsible for various functions throughout the body, including regulating a woman’s reproductive functions such as the normal development of eggs in the ovaries. An absence of ovulation, which is caused by abnormal hormone signals, can cause heavy bleeding and a thickened uterine lining.

An ultrasound is the most common diagnostic test used to determine the presence of uterine fibroids. Ultrasounds are an imaging test that uses sound waves to make “pictures” of organs in the body. An ultrasound can be performed either through the abdomen or vagina (transvaginal ultrasound) and lasts about 30 minutes. Using an ultrasound, a physician can observe the shape, size and location of the fibroids.

Other tests that may be used in the diagnosis of uterine fibroids include:

• Blood tests. A physician can order analysis of a patient’s blood sample to rule out cancer, bleeding disorders and to check the levels of reproductive hormones produced by the ovaries. A blood test also can determine the presence of iron-deficiency anemia, which can result from prolonged abnormal uterine bleeding.
  
  
• Endometrial biopsy. A sample of the lining of the uterus may be obtained for laboratory analysis to rule out cancer and check for other causes of abnormal uterine bleeding.
  
  
• Other imaging tests. These tests are often useful in determining if a uterine fibroid is indeed present or if another type of tumor is present. Common imaging studies that a physician may use to examine the uterus and surrounding pelvic organs include:
  
  
• Hysteroscopy. During this test, the physician inserts a small, lighted tube (hysteroscope) through the cervix and into the uterus. The tube releases a gas or liquid that expands the uterus and allows the physician a closer view of the uterine walls and the openings of the fallopian tubes. This test is frequently performed in conjunction with an endometrial biopsy or to surgically remove a fibroid that protrudes into the uterine cavity (submucosal).
  
  
• Hysterosalpingogram. During the test, the physician inserts a small, thin tube (catheter) into the cervix. The catheter releases a contrast medium (dye) that flows into the uterus. The dye outlines the shape of the uterine body and fallopian tubes and makes any fibroids visible on x-ray images.
  
  
• Sonohysterography. Saline solution, and sometimes air, is delivered by a catheter into the uterus to help the physician observe these structures with an ultrasound. The saline expands the uterus and allows detection of fibroids and other abnormalities that may not have been visible during an abdominal or transvaginal ultrasound. When air is also injected, the presence or absence of bubbles can indicate to the physician whether there is blockage in the fallopian tubes.

Other imaging tests that may be used to detect uterine fibroids include computed axial tomography (CAT scan) and magnetic resonance imaging (MRI). These tests are not routinely needed to diagnose fibroids, but may help clarify the diagnosis in some cases.

Most uterine fibroids do not require treatment, especially if no symptoms are present. In such cases, a physician, typically a gynecologist, will perform periodic pelvic examinations and imaging tests (e.g., ultrasound) to determine if the fibroids are changing in size and monitor the development of symptoms. This is known as “watchful waiting” and patients may need to consult the gynecologist every six months to a year or as determined by their physician.

When symptoms are present, treatment will depend on several factors including the severity of the symptoms, the age of the patient and whether she plans to become pregnant in the future.

Nonsteroidal anti-inflammatory drugs (NSAIDs) may provide some relief of menstrual symptoms (e.g., pain, cramps) exacerbated by the fibroids. A physician also may recommend iron supplementation to prevent or treat anemia due to heavy menstrual blood loss.

Sometimes, a physician may prescribe hormonal medications to treat the abnormal uterine bleeding and pelvic pain. Certain hormone medications can temporarily shrink the fibroids. However, after treatment is stopped the fibroids typically will continue to grow. Hormonal therapy used in the treatment of fibroids can include:

• Birth control pills. Oral contraceptives can help reduce heavy periods and alleviate symptoms. However, they do not affect the size of the fibroids.
  
  
• Gonadotrophin-releasing hormone (GnRH) agonists. This medication reduces the production of the female hormones estrogen and progesterone by the ovaries, thereby causing the fibroids to shrink in size. GnRH agonists are typically used as an adjunct to surgery for removal of large fibroids. Making the fibroids smaller before their removal may lessen blood loss during surgery. However, GnRH agonists sometimes may make surgical removal more difficult because the fibroids can be harder to locate after treatment due to shrinkage.
  
  In some cases, a physician may prescribe this type of treatment for women who are very near menopause. However, GnRH agonists are not typically recommended for longer than 6 months because they can result in a loss of bone density and increase the risk of osteoporosis. In addition, after use of GnRH agonists is discontinued, fibroids rapidly enlarge. Because GnRH agonists induce a chemical menopause, patients often stop having their periods and can experience side effects such as hot flashes and vaginal dryness during treatment. These medications are usually administered by needle injection into a large muscle.
  
  
• Androgens. Medications containing the hormone testosterone (e.g., danazol) also can help reduce the size of fibroids and control associated symptoms. However, because these drugs sometimes have unpleasant side effects including weight gain, acne, unwanted hair growth (hirsutism), deepening of the voice and depression they are not a popular treatment option for many women.

In cases where the fibroids are large, numerous and causing severe symptoms or compromising the health of the uterus and other pelvic organs, surgical removal is often necessary. Surgery also may be recommended in cases in which the fibroids are interfering with a woman’s ability to become pregnant. Surgical treatment of uterine fibroids includes:

• Myomectomy. Surgical removal of the fibroids from the uterine wall. It is recommended for women who desire to retain the uterus or become pregnant. However, like all surgeries, myomectomy may carry risks, such as pelvic adhesions, trauma to internal organs, infection and, rarely, rupturing of the uterus. The type of myomectomy performed depends on the size, number and location of the fibroids:
  
  
• Abdominal myomectomy. In this procedure, the physician makes an incision in the abdomen to expose the uterus and excise the fibroids from the uterine wall muscle. This surgery can be performed to remove multiple fibroids.
  
  
• Hysteroscopic myomectomy. A tube with a light at the end (hysteroscope) is inserted into the vagina, through the cervix and into the uterus during this procedure. The surgeon can observe the fibroids through the hysteroscope and remove them. This surgery is only performed on fibroids that are located inside the uterus.
  
  
• Laparoscopic myomectomy. In this surgery, fibroids are removed through a small lighted viewing tube (laparoscope) inserted through a small incision in the abdomen. The laparoscope allows the surgeon to locate the fibroids and remove them. This procedure is often performed on women with one or two small fibroids located on the outer surface of the uterus.
  
  
• Uterine artery embolization (UAE). Also called uterine fibroid embolization (UFE), this is a newer technique that has demonstrated a significant reduction of symptoms with few serious complications. During embolization, a physician inserts a small, thin tube (catheter) into a large blood vessel in the groin and threads it up to blood vessels near a fibroid. Tiny particles made of plastic or gelatin are then injected into the blood vessels that feed the fibroid. These particles clog the blood vessels and significantly reduce the blood supply to the fibroid, causing it to shrink and degenerate (die off) within a few days to two weeks. Although pregnancy and normal deliveries have been reported in some patients who have undergone embolization, pregnancy is not recommended afterward and the procedure may affect ovarian function and lead to infertility.
  
  
• Endometrial ablation. This procedure uses heat to destroy the entire lining of the uterus (endometrium). Endometrial ablation will either end the menstrual period or significantly reduce its flow. During the procedure, the surgeon can remove or shave down fibroids that protrude into the uterine cavity (submucosal). However, this technique does not work on large fibroids or those that are located outside the interior lining of the uterus. Ablation also is not recommended for women who want to have children.
  
  
• Hysterectomy. Complete surgical removal of the uterus. A surgeon can remove the uterus through an abdominal incision or through the vagina and in some cases with the aid of a laparoscope. About half of all hysterectomies in the United States are performed to treat uterine fibroids, according to the American Society for Reproductive Medicine. It is the most radical way of treating uterine fibroids and accompanying symptoms, but it is 100-percent effective. However, this surgery is not recommended for women who want to retain their organs or bear children.

The newest treatment for uterine fibroids is a procedure called focused ultrasound surgery (FUS, but also called MRgFUS), which was approved by the Food and Drug Administration (FDA) in 2004. FUS is noninvasive and preserves the uterus. During FUS, a woman lies on a special type of MRI scanner machine and then a contrast dye is administered, which allows physicians to visualize the uterus and surrounding organs. Using FUS the physician can locate and destroy uterine fibroids without making any incisions. Focused high-frequency, high-energy sound waves target and destroy the fibroids. FUS can take up to several hours because it is performed on an on- and off-again fashion until the entire tumor is destroyed. In some cases, a second treatment session may be necessary. FUS is performed on an outpatient basis and side effects are minimal. However, FUS is costly and it may not be offered at most facilities because it requires special equipment. In addition, the long-term effectiveness of FUS has not been proven.

Patients are urged to discuss all treatment options with their physician to determine which type is best for them.

Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor or healthcare professional the following questions related to uterine fibroids:

1. How will I know if I have uterine fibroids?
   
   
2. What are the chances that the symptoms caused by my fibroids will disappear without treatment?
   
   
3. What type of tests might I need for my condition?
   
   
4. What will these tests tell you?
   
   
5. Should I use birth control pills to prevent fibroids?
   
   
6. How will I know if my condition is a medical emergency?
   
   
7. Will fibroids affect my ability to become pregnant?
   
   
8. If I have uterine fibroids, does it mean my daughters will develop them too?
   
   
9. I want to get pregnant in the future. What type of treatment do you recommend for my fibroids?
   
   
10. Are my fibroids cancerous? Could they turn cancerous in the future?