Uterine Fibroids

Uterine fibroids are benign (not cancer) growths that develop from the muscle tissue of the uterus. They also are called leiomyomas or myomas. They are the most common type of growth found in a woman's pelvis.

The size, shape, and location of fibroids can vary greatly. They may be inside the uterus, on its outer surface or within its wall, or attached to it by a stem-like structure.

Fibroids can range in size from small, pea-sized growths to large, round ones that may be more than 5 to 6 inches wide. As they grow, they can distort the inside as well as the outside of the uterus. Sometimes fibroids grow large enough to completely fill the pelvis or abdomen.

There may be only one fibroid or many of varying sizes. A fibroid may remain very small for a long time and suddenly grow rapidly, or grow slowly over a number of years.

Fibroids are most common in women age 30 to 40, but they can occur at any age. Fibroids occur more often in Black women than in White women. They also seem to occur at a younger age and grow more quickly in Black women. These differences may be due to racism and inequities in society, which can increase the risk of health problems. Also, fibroids may run in families, so a family history of fibroids may be a factor as well.

It is not clear what causes fibroids. Some research suggests that they develop from misplaced cells that are in the body before birth. The female hormones estrogen and progesterone appear to be involved in their growth.

Levels of these hormones can increase or decrease throughout your life. For example, menopause causes a decrease in estrogen. Fibroids often shrink when a woman enters menopause. Hormonal medications that contain estrogen, such as birth control pills, may cause fibroids to grow.

Fibroids may have the following symptoms:

• Changes in menstruation

  • Longer, more frequent, or heavy menstrual periods

  • Menstrual pain (cramps)

  • Vaginal bleeding at times other than menstruation

  • Anemia (from blood loss)

• Pain

  • In the abdomen or lower back (often dull, heavy and aching, but may be sharp)

  • During sex

• Pressure

  • Difficulty urinating or frequent urination

  • Constipation, rectal pain, or difficult bowel movements

  • Abdominal cramps

• Enlarged uterus and abdomen

• Miscarriages

• Infertility

Sometimes fibroids cause no symptoms at all. Fibroids may be found during a routine pelvic exam or during tests for other problems.

Most fibroids do not cause problems, but there can be complications. Fibroids that are attached to the uterus by a stem may twist and can cause pain, nausea, or fever. Fibroids that grow rapidly, or those that start breaking down, may also cause pain. Rarely, they can be associated with cancer.

A very large fibroid may cause swelling of the abdomen. This swelling can make it hard to do a thorough pelvic exam.

Fibroids may cause infertility, although other causes are more common. Other factors should be explored before fibroids are considered the cause of infertility. When fibroids are thought to be a cause, many women are able to get pregnant after they are treated.

The first signs of fibroids may be found during a routine pelvic exam. A number of tests may show more information about fibroids:

• An ultrasound exam uses sound waves to create a picture of the uterus and other pelvic organs.

• Hysteroscopy uses a thin device (the hysteroscope) to see the inside of the uterus. It is inserted through the vagina and cervix (opening of the uterus). This lets your health care professional see fibroids inside the uterine cavity.

• Hysterosalpingography is a special X-ray test. It may find abnormal changes in the size and shape of the uterus and fallopian tubes.

• Sonohysterography is a test in which fluid is put into the uterus through the cervix. Ultrasound is then used to show the inside of the uterus. The fluid provides a clear picture of the uterine lining.

• Laparoscopy uses a thin device (the laparoscope) to help your health care professional see the inside of the abdomen. It is inserted through a small cut just below or through the belly button. Fibroids on the outside of the uterus can be seen with the laparoscope.

Imaging tests, such as magnetic resonance imaging (MRI) and computed tomography (CT) scans, may be used but are rarely needed. Some of these tests may be used to track the growth of fibroids over time.

Fibroids that do not cause symptoms, are small, or occur in a woman who is nearing menopause often do not require treatment. Certain signs and symptoms may signal the need for treatment:

• Heavy or painful menstrual periods that cause anemia or that disrupt your normal activities

• Bleeding between periods

• Uncertainty whether the growth is a fibroid or another type of tumor, such as an ovarian tumor

• Rapid increase in growth of the fibroid

• Infertility

• Pelvic pain

There are many treatment options for fibroids. The choice of treatment depends on factors such as your own wishes and the size and location of the fibroids.

Medications are an option for some women with fibroids. Medications may reduce the heavy bleeding and painful periods that fibroids sometimes cause. They may not prevent the growth of fibroids. Surgery often is needed later. Treatment with medications includes the following options:

• Birth control pills and other types of hormonal birth control methods—These are often used to control heavy bleeding and painful periods. A drawback is that this treatment may cause the fibroids to increase slightly in size. For some women, the benefits of managing heavy bleeding and pain with hormonal birth control may outweigh the risk of fibroids growing larger.

• Gonadotropin-releasing hormone (GnRH) agonists—These medications stop the menstrual cycle and can shrink fibroids. They are sometimes used before surgery to reduce the risk of bleeding. GnRH agonists have many side effects, including bone loss, osteoporosis, vaginal dryness, and night sweats. Taking low-dose estrogen or progestin helps reduce these side effects. This is called "add-back therapy." GnRH agonists are typically used for less than 6 months without add-back therapy, or for 12 months with add-back therapy. After a woman stops taking a GnRH agonist, her fibroids usually return to their previous size.

• GnRH antagonists with hormonal add-back therapy—These medications can be used to treat heavy bleeding for up to 2 years. They do not shrink fibroids. Hormonal medication (add-back therapy) helps reduce side effects, including hot flashes and bone loss.

• Progestin-releasing intrauterine device (IUD)—This option is for women with fibroids that do not distort the inside of the uterus. It reduces heavy and painful bleeding but does not treat the fibroids themselves.

• Tranexamic acid—This medication is used to treat heavy bleeding. It reduces the blood lost during your period, but does not stop your periods.

Many other medications are being studied for the treatment of fibroids.

Myomectomy is the surgical removal of fibroids while leaving the uterus in place. Fibroids do not regrow after surgery, but new fibroids may develop. If they do, more surgery may be needed.

Because you keep your uterus, you may still be able to have children after a myomectomy. But sometimes a myomectomy causes internal scarring that can lead to infertility. If you do get pregnant after a myomectomy, you may need to have a cesarean birth.

Hysterectomy is the removal of the uterus. The ovaries may or may not be removed. Hysterectomy is done when other treatments have not worked or are not possible or the fibroids are very large. You are no longer able to have children after having a hysterectomy.

Myomectomy may be done in a number of ways:

• Laparotomy
• Laparoscopy
• Hysteroscopy

The method used depends on the location and size of the fibroids. In laparotomy, an incision (cut) is made in the abdomen. The fibroids are removed through the incision. In laparoscopy, a laparoscope is used to view the inside of the pelvis. Other tools are inserted through another small incision to remove the fibroids.

Hysteroscopy can be used to remove fibroids that protrude into the cavity of the uterus. A resectoscope is inserted through the hysteroscope. The resectoscope destroys fibroids with electricity or a laser beam. Although it cannot remove fibroids deep in the walls of the uterus, it can often control the bleeding these fibroids cause. In most cases, an overnight stay in the hospital is not necessary.

Myomectomy has risks, including bleeding and infection. Hysteroscopy may cause other problems related to the use of fluid during the procedure. Your health care professional can explain all of the risks to you.

In a hysterectomy, the uterus may be removed through a cut in the abdomen or through the vagina. The method used depends on the size of the fibroids.

For pain relief, you may be given general anesthesia, which puts you to sleep, or regional anesthesia, which blocks feeling in the lower part of your body. You may need to stay in the hospital for a few days after this procedure.

Read Hysterectomy to learn more.

Other treatment options include the following:

• Uterine artery embolization (UAE)—In this procedure, tiny particles (about the size of grains of sand) are injected into the blood vessels that lead to the uterus. The particles cut off the blood flow to the fibroid and cause it to shrink. UAE can be done as an outpatient procedure in most cases. The effect of UAE on future pregnancies is not clear. Read Uterine Artery Embolization to learn more.

• Radiofrequency ablation (RFA)—This procedure uses energy and heat to shrink the size of fibroids. RFA can be done with laparoscopy, which involves only small incisions. An ultrasound probe and a laparoscope are inserted into the abdomen to help find the fibroids. Then thin needles are inserted through the abdomen into the fibroids, to heat and destroy the fibroid tissue. RFA can also be done through the vagina or through the cervix, instead of through the abdomen. Complications are not common. More research is needed to understand the effect of RFA on future pregnancies.

• MRI-guided ultrasound surgery—In this new approach, ultrasound waves are used to destroy fibroids. The waves are directed at the fibroids through the skin with the help of magnetic resonance imaging. You may need more treatments after this procedure. More research is needed to say whether this procedure is effective. A small amount of data show:

  • This procedure may reduce the size of fibroids.

  • This procedure is less effective than UAE.

Anemia: Abnormally low levels of red blood cells in the bloodstream. Most cases are caused by iron deficiency (lack of iron).

Cervix: The lower, narrow end of the uterus at the top of the vagina.

Cesarean Birth: Birth of a fetus from the uterus through an incision made in the woman’s abdomen.

Computed Tomography (CT): A type of X-ray that shows internal organs and structures in cross section.

Estrogen: A female hormone produced in the ovaries.

Fetus: The stage of human development beyond 8 completed weeks after fertilization.

Fallopian Tubes: Tubes through which an egg travels from the ovary to the uterus.

Gonadotropin-releasing Hormone (GnRH): A hormone made in the brain that tells the pituitary gland when to produce follicle-stimulating hormone (FSH) and luteinizing hormone.

Hysterectomy: Surgery to remove the uterus.

Hysterosalpingography: A special X-ray procedure in which a small amount of fluid is placed in the uterus and fallopian tubes to find abnormal changes or see if the tubes are blocked.

Hysteroscopy: A procedure in which a lighted telescope is inserted into the uterus through the cervix to view the inside of the uterus or perform surgery.

Intrauterine Device (IUD): A small device that is inserted and left inside the uterus to prevent pregnancy.

Laparoscopy: A surgical procedure in which a thin, lighted telescope called a laparoscope is inserted through a small incision (cut) in the abdomen. The laparoscope is used to view the pelvic organs. Other instruments can be used with it to perform surgery.

Laparotomy: A surgical procedure in which an incision is made in the abdomen.

Magnetic Resonance Imaging (MRI): A test to view internal organs and structures by using a strong magnetic field and sound waves.

Menopause: The time when a woman's menstrual periods stop permanently. Menopause is confirmed after 1 year of no periods.

Menstruation: The monthly shedding of blood and tissue from the uterus that happens when a woman is not pregnant.

Osteoporosis: A condition of thin bones that could allow them to break more easily.

Pelvic Exam: A physical examination of a woman’s pelvic organs.

Progesterone: A female hormone that is made in the ovaries and prepares the lining of the uterus for pregnancy.

Progestin: A synthetic form of progesterone that is similar to the hormone made naturally by the body.

Resectoscope: A slender telescope with an electrical wire loop or roller-ball tip used to remove or destroy tissue.

Sonohysterography: A procedure in which sterile fluid is injected into the uterus through the cervix while ultrasound images are taken of the inside of the uterus.

Tranexamic Acid: A drug to treat or prevent heavy bleeding.

Ultrasound Exam: A test in which sound waves are used to examine inner parts of the body. During pregnancy, ultrasound can be used to check the fetus.

Uterus: A muscular organ in the female pelvis. During pregnancy, this organ holds and nourishes the fetus. Also called the womb.

Uterine Artery Embolization: A procedure to block the blood vessels to the uterus. This procedure is used to stop bleeding after delivery. It is also used to stop other causes of bleeding from the uterus.

Vagina: A tube-like structure surrounded by muscles. The vagina leads from the uterus to the outside of the body.