Uterine Fibroids: What Are They?
Uterine fibroids are noncancerous tumors that grow along or within the walls of the uterus. They are primarily made up of smooth muscle cells, along with small amounts of other tissues. They range dramatically in size. Some fibroids are microscopic, whereas others may be eight or more inches across. On average, these tumors range from about the size of a large marble to a bit smaller than a baseball.
Sometimes fibroids are found alone, and other times they grow in clusters. Many of them grow, but others shrink or remain the same size as time passes.
To understand this most common noncancerous tumor in women of childbearing age, read along as we provide medically-reviewed information about uterine fibroid symptoms, treatments, and pictures. Along the way you will learn sometimes surprising facts about these growths, arming yourself with useful information.
Uterine Fibroids and Cancer
Fibroid tumors are benign by definition. When a smooth muscle tumor is cancerous, it is called leiomyosarcoma and occurs only once in every 1,000 smooth muscle tumors of the uterus. This type of cancer is not believed to arise from benign fibroids. Your chances of developing a cancerous growth do not increase because you have uterine fibroids, nor does having them increase your chances of getting other uterine cancers.
Uterine Fibroid Symptoms
Most women with fibroids (also known as leiomyomas) experience no symptoms. But for at least 25% of patients, some symptoms will occur. These may involve abdominal pressure, which can feel like fullness in the pelvic region or bloating in the pelvis or stomach. Large leiomyomas can enlarge the lower stomach area, sometimes giving the false appearance of pregnancy.
Uterine fibroids can also impact your monthly menstrual cycle. This can take various forms. Some experience mild to severe cramping and pain. Others will find their bleeding is heavier, and their heavy periods sometimes include blood clots. Others find their menstruation lasts longer or becomes more frequent. It can also cause spotting or bleeding in between menstruation.
Other potential symptoms of uterine fibroids include pain during sexual intercourse and lower back pain. Because the leiomyomas can press against the bladder, they may provoke frequent urination.
Endometriosis or Fibroids?
What's the difference between endometriosis and fibroid symptoms? Both uterine fibroids and endometriosis cause pelvic pain, and sometimes the two conditions can be confused. Someone with either endometriosis or fibroids may experience severe menstrual pain, as well as pain between periods.
What Is Endometriosis?
Endometriosis occurs when the tissue that lines the womb begins to grow outside of it—usually in the pelvic cavity. It can also appear on the ovaries, fallopian tubes, on the bowels or bladder, and other nearby areas.
Endometriosis is less common than uterine fibroids. One study found that about 2% of women aged 15-50 are believed to have endometriosis.
What Causes Uterine Fibroids?
The cause of uterine fibroids is still unknown. That's frustrating, because determining their cause could help scientists discover remedies and cures.
We do know that someone who begins her periods earlier in life is more likely to develop uterine fibroids. There also seems to be an elevated risk for women who take female hormones, but this does not apply to those on birth control pills.
While no one knows for certain what causes them, theories about the cause of leiomyomas abound. Some researchers suspect that growth hormones, genetic changes, estrogen, progesterone, or cells that are misplaced during fetal development may play a role in the development of fibroids.
None of these theories works to completely explain the condition, however. Research into the cause is ongoing.
Types of Uterine Fibroids
Uterine fibroids are classified based on where they occur in the uterus.
Subserosal fibroids grow outside of the uterus and are found on the serosa. The serosa is the thin, outermost layer of the uterus. With the help of ligaments, the serosa supports the womb within the pelvic cavity. Subserosal fibroids can be either sessile or pendunculated. Pendunculated subserosal fibroids grow on small stalks that project away from the outside of the womb.
Intramural fibroids are the most common type of fibroid. They form in the myometrium of the uterus. The myometrium is the middle layer of the uterus, and it is the thickest. Composed of smooth muscle, the myometrium is what contracts during a period to remove the endometrial lining. This type of leiomyoma may distort the shape of the womb.
Submucosal fibroids account for about 5% of all uterine fibroids. They occur within the endometrium, the thin, innermost layer that lines the inside of the uterus. They can be either pendunculated or sessile, like subserosal fibroids. Pendunculated submucosal fibroids grow on small stalks that project into the inner uterus.
Although these types are the definitions physicians use, they are limited. Most fibroids are actually hybrids spanning more than one area of the womb. You may also hear of parasitic fibroids, which receive blood from somewhere other than the uterus. Sometimes small fibroids—those smaller than four millimeters in diameter—are called seedling fibroids.
Uterine Fibroid Prevalence
Leiomyomas are very common. It is estimated that by age 50, as many as 70% to 80% of women will have them. Although their cause remains unknown, various factors indicate a higher risk of their occurrence.
One risk factor is age. Once women reach their 30s and 40s, their risk increases. Women in their 30s are the ones most likely to acquire leiomyomas. After menopause, leiomyomas tend to shrink.
Another risk factor is family history. When your family member has the condition, your likelihood of experiencing them increases. If that family member is your mother, your odds of developing leiomyomas is about three times higher than average.
Race also plays a part in determining one's likelihood of developing leiomyomas. Black Americans are slightly more likely than Caucasian Americans to develop them later in life, although for women under age 35 the likelihood is about the same regardless of race. Asian women are less likely to develop fibroids.
Diet plays another important part in the development of leiomyomas. Some foods seem to encourage them, while other foods seem to discourage them. Diets linked with a higher risk include a lot of red meat (beef, ham). Diets linked with a lower risk include plenty of green vegetables. Eating dairy products (milk, yogurt, cheese, ice cream, etc.) at least once a day was shown in one large study to reduce the risk. Eating enough micronutrients, including iron, vitamin A, and vitamin D, may also help lower a patient's risk.
Health Complications: Anemia
Because this condition can cause heavy bleeding, those affected may experience anemia or iron deficiency. Often this is mild and can be alleviated with iron pills and diet changes. If it goes untreated though, anemia can cause exhaustion and lethargy. In severe cases, heart problems can result from anemia.
Health Complications of Pregnancy
Most women with leiomyomas have normal pregnancies. Nevertheless, leiomyomas are associated with increased risk for a range of fertility and pregnancy problems. The growths are associated with infertility, recurrent miscarriage, labor complications, and early labor. They also make breech births more likely. Because of the increase in labor complications and breech births, women with uterine fibroids are six times more likely to give birth via Cesarean section.
Uterus Health: When to Call a Doctor
There are a few complications of leiomyomas that will need a doctor's care. Go see your doctor if you experience heavy periods, or if your periods become more painful. Talk to a doctor if you find it difficult to control your urination or if you urinate more frequently. If you notice the length of your periods increase for more than three cycles, or if you experience persistent heaviness or pain in your pelvis or lower abdomen, go see a doctor.
How to Know If You Have Uterine Fibroids
Because there are often no symptoms, you may be wondering how you can know for sure if you have this condition. The answer involves a trip to the doctor.
If your leiomyomas are big enough, a doctor may be able to feel them during a pelvic exam. Smaller ones can be picked up via ultrasound. Ultrasound is the most common way to diagnose leiomyomas with advanced imaging, but CT scans and MRIs are also used. Another method is saline infusion sonography, during which salt water is injected into the womb to help provide clear ultrasound images. This may become the most useful method, as it can distinguish leiomyomas from other lesions.
If you are interested in becoming pregnant, your doctor may suggest a test known as a hysterosalpingogram. This test outlines the uterus and fallopian tubes and can be useful in spotting abnormalities that your gynecologist should be aware of.
Fibroid Treatment: Pain Medicine
What treatments are available for fibroids? Since one of the common symptoms of this condition is painful periods, you may seek medication for additional care. Over-the-counter pain medicines like acetaminophen (Tylenol), ibuprofen (Advil) and naproxen can help ease the pain.
Fibroid Treatment: Birth Control
Periods can be heavier for those with uterine fibroids. Both standard birth control pills and their low-dose counterparts can help care for the symptom of heavy bleeding. Injected birth control (including Depo-Provera) can also help control bleeding during periods.
Additional Hormone Therapies for Fibroids
Gonadotropin-releasing hormone agonists (GnRHa) are another treatment used to control the development of uterine fibroids. Taken as either an injection, implant, or nasal spray, these hormones causes the amount of estrogen in the body to drop, which can cause the leiomyomas to stop growing or shrink. For this reason, GnRHa are sometimes used prior to surgery to make the tumors easier to remove. Most women do not get their periods on GnRHa drugs, which brings further relief for fibroid symptoms and can help the blood count readjust after a bout of anemia.
GnRHa are usually safe for women, and most can use the hormone without any negative consequences. However some experience side effects similar to menopause symptoms, such as hot flashes, mood swings, decreased libido, sleeplessness, headaches, and joint pain. Because it can cause bone thinning, GnRHa treatment is usually limited to six months—often the six months prior to surgery. After treatment, most fibroids quickly grow back to their original size.
GnRHa drugs are very expensive. Some insurance plans will require you to cover some or all of their cost.
Treatment: Uterine Fibroid Embolization
Embolization is a nonsurgical procedure that deprives the fibroids of blood, causing them to shrink. To perform an embolization, a doctor will make a small incision into the groin area in order to place a thin tube (catheter) into a large blood vessel. The tube is flexible, allowing it to snake along inside the blood vessel until it arrives near the leiomyoma, at which time a solution of tiny plastic or gel particles is injected, which blocks the blood supply to the growth.
This procedure usually does not harm the uterus itself, which continues to be supplied by other blood vessels. Embolization shrinks leiomyomas by half their size or more.
This therapy isn't for everyone. The best candidates are those experiencing heavy bleeding whose uterine fibroids are causing pain or pressure on the bladder or rectum. The long-term effects on pregnancy are not fully known, though some report an increased risk of miscarriage. For this reason, embolization is only recommended for those who do not wish to become pregnant in the future. The procedure is usually safe but can lead to complications in some cases. If the blocking solution drifts to the ovarian artery, it can cause problems with ovarian function. Some research tells us that while the treatment is generally successful, as many as one-third of patients will find that their leiomyomas reappear within five years.
Surgical therapy comes down to three options: endometrial ablation, myomectomy, and hysterectomy.
The lining of the uterus (the endometrium) is destroyed with endometrial ablation. This is used to remove small leiomyomas within the uterus. The procedure can be performed via freezing, laser, electric current, instrumentation, or boiling water. Often a heated balloon is used. At other times a device is employed that uses microwave energy to destroy the lining.
Endometrial ablation makes pregnancy unlikely, but not impossible. When pregnancy does occur, the pregnancy carries a higher risk of miscarriage and other complications.
Most women recover quickly from this outpatient procedure. About half of patients will no longer bleed during their periods. About 30% will experience much lighter bleeding. Although complications can occur, they are unusual with most methods of endometrial ablation.
For women who wish to become pregnant, myomectomy is the most promising surgical option. Myomectomy removes leiomyomas while leaving healthy womb tissue intact.
This surgery can be performed in a variety of ways and may be classified as major surgery depending on the extensiveness of the procedure and the placement of the leiomyomas. For this reason, complications vary depending on the details of a given procedure.
One drawback to myomectomy care is that although the existing leiomyomas will be destroyed, new leiomyomas may develop later on.
The only certain and permanent treatment for uterine fibroids is hysterectomy. About 200,000 hysterectomies are performed every year in the US for treatment of leiomyoma. Hysterectomy involves the removal of part or all of the womb, and sometimes the ovaries and fallopian tubes as well.
A patient will be infertile following hysterectomy surgery. It is a major surgery, though health risks are among the lowest of all major surgeries. Nonetheless serious complications can occur, including blood clots, injury to the urinary tract and bowels, severe infection and, rarely, death.
Recovery time for hysterectomy is typically several weeks.
A promising treatment for leiomyomas involves the use of magnetic resonance imaging (MRI). The MRI is used to search for the leiomyomas. Then a doctor can direct ultrasound waves at the leiomyomas in order to superheat them and shrink them. This has the advantage of sparing the surrounding uterine tissue, though it may affect the function of the ovaries. This procedure typically takes around three hours. It is recommended for women who have a small number of large leiomyomas.
This technique is only approved for women who do not wish to become pregnant, but some pregnancies have occurred following ultrasound therapy. About 25% of patients must return after one year for a second procedure. Women who undergo this procedure can go home the same day and usually return to their daily routine the next day. This therapy is relatively new, so some hospitals won't offer it, and some insurance plans do not cover it.
Prevention: Vigorous Exercise
There is no known method of preventing leiomyomas, but some studies suggest exercise may be useful. A survey of about 1,200 women with the growths found that light or moderate exercise had no effect on a woman's risk of developing the tumors. However vigorous exercise for three or more hours per week reduced the risk by 30% to 40% in this study. Another study shows a reduced risk for women who participated in sports as girls. While these studies do not conclusively prove that exercise can prevent leiomyomas, the results are interesting and merit further investigation.
One study speculated that exercise could reduce the circulation of sex hormones and insulin levels, and that this may explain how regular, intense workouts could reduce the risk. Exercise also helps prevent obesity, which carries with it a higher risk of developing the tumors.
One of the big challenges for many women with symptoms of this condition is keeping their iron levels in balance. Anemia is a deficiency of red blood cells. Red blood cells are iron-rich, and lack of iron (usually due to blood loss) is the most common cause of anemia.
To maintain a healthy level of iron, doctors recommend a diet rich in high-iron foods such as beef, fish, poultry, leafy green vegetables, dried fruit, legumes, and nuts. A lot of food is also iron-fortified, such as many breads and cereals. Sometimes iron supplements are recommended as well. Talk to your doctor for recommendations on the healthiest ways for you to increase your iron levels.
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- Peggy Firth and Susan Gilbert for WebMD
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