Give us feedback on this page |
[Printer-friendly version -- PDF file, 260 Kb]
See also:
Fibroids are muscular tumors that grow in the wall of the uterus (womb). Another medical term for fibroids is "leiomyoma" (leye-oh-meye-OH-muh) or just "myoma". Fibroids are almost always benign (not cancerous). Fibroids can grow as a single tumor, or there can be many of them in the uterus. They can be as small as an apple seed or as big as a grapefruit. In unusual cases they can become very large.
![]() |
![]() |
About 20 percent to 80 percent of women develop fibroids by the time they reach age 50. Fibroids are most common in women in their 40s and early 50s. Not all women with fibroids have symptoms. Women who do have symptoms often find fibroids hard to live with. Some have pain and heavy menstrual bleeding. Fibroids also can put pressure on the bladder, causing frequent urination, or the rectum, causing rectal pressure. Should the fibroids get very large, they can cause the abdomen (stomach area) to enlarge, making a woman look pregnant.
There are factors that can increase a woman's risk of developing fibroids.
Most fibroids grow in the wall of the uterus. Doctors put them into three groups based on where they grow:
Some fibroids grow on stalks that grow out from the surface of the uterus or into the cavity of the uterus. They might look like mushrooms. These are called pedunculated (pih-DUHN-kyoo-lay-ted) fibroids.
Most fibroids do not cause any symptoms, but some women with fibroids can have:
No one knows for sure what causes fibroids. Researchers think that more than one factor could play a role. These factors could be:
Because no one knows for sure what causes fibroids, we also don't know what causes them to grow or shrink. We do know that they are under hormonal control—both estrogen and progesterone. They grow rapidly during pregnancy, when hormone levels are high. They shrink when anti-hormone medication is used. They also stop growing or shrink once a woman reaches menopause.
Fibroids are almost always benign (not cancerous). Rarely (less than one in 1,000) a cancerous fibroid will occur. This is called leiomyosarcoma (leye-oh-meye-oh-sar-KOH-muh). Doctors think that these cancers do not arise from an already-existing fibroid. Having fibroids does not increase the risk of developing a cancerous fibroid. Having fibroids also does not increase a woman's chances of getting other forms of cancer in the uterus.
Women who have fibroids are more likely to have problems during pregnancy and delivery. This doesn't mean there will be problems. Most women with fibroids have normal pregnancies. The most common problems seen in women with fibroids are:
Talk to your obstetrician if you have fibroids and become pregnant. All obstetricians have experience dealing with fibroids and pregnancy. Most women who have fibroids and become pregnant do not need to see an OB who deals with high-risk pregnancies.
Your doctor may find that you have fibroids when you see her or him for a regular pelvic exam to check your uterus, ovaries, and vagina. The doctor can feel the fibroid with her or his fingers during an ordinary pelvic exam, as a (usually painless) lump or mass on the uterus. Often, a doctor will describe how small or how large the fibroids are by comparing their size to the size your uterus would be if you were pregnant. For example, you may be told that your fibroids have made your uterus the size it would be if you were 16 weeks pregnant. Or the fibroid might be compared to fruits, nuts, or a ball, such as a grape or an orange, an acorn or a walnut, or a golf ball or a volleyball.
Your doctor can do imaging tests to confirm that you have fibroids. These are tests that create a "picture" of the inside of your body without surgery. These tests might include:
You might also need surgery to know for sure if you have fibroids. There are two types of surgery to do this:
A second opinion is always a good idea if your doctor has not answered your questions completely or does not seem to be meeting your needs.
Most women with fibroids do not have any symptoms. For women who do have symptoms, there are treatments that can help. Talk with your doctor about the best way to treat your fibroids. She or he will consider many things before helping you choose a treatment. Some of these things include:
If you have fibroids but do not have any symptoms, you may not need treatment. Your doctor will check during your regular exams to see if they have grown.
Medications
If you have fibroids and have mild symptoms, your doctor may suggest taking medication. Over-the-counter drugs such as ibuprofen or acetaminophen can be used for mild pain. If you have heavy bleeding during your period, taking an iron supplement can keep you from getting anemia or correct it if you already are anemic.
Several drugs commonly used for birth control can be prescribed to help control symptoms of fibroids. Low-dose birth control pills do not make fibroids grow and can help control heavy bleeding. The same is true of progesterone-like injections (e.g., Depo-Provera®). An IUD (intrauterine device) called Mirena® contains a small amount of progesterone-like medication, which can be used to control heavy bleeding as well as for birth control.
Other drugs used to treat fibroids are "gonadotropin releasing hormone agonists" (GnRHa). The one most commonly used is Lupron®. These drugs, given by injection, nasal spray, or implanted, can shrink your fibroids. Sometimes they are used before surgery to make fibroids easier to remove. Side effects of GnRHas can include hot flashes, depression, not being able to sleep, decreased sex drive, and joint pain. Most women tolerate GnRHas quite well. Most women do not get a period when taking GnRHas. This can be a big relief to women who have heavy bleeding. It also allows women with anemia to recover to a normal blood count. GnRHas can cause bone thinning, so their use is generally limited to six months or less. These drugs also are very expensive, and some insurance companies will cover only some or none of the cost. GnRHas offer temporary relief from the symptoms of fibroids; once you stop taking the drugs, the fibroids often grow back quickly.
Surgery
If you have fibroids with moderate or severe symptoms, surgery may be the best way to treat them. Here are the options:
Yes. Researchers are looking into other ways to treat uterine fibroids. The following methods are not yet standard treatments; so your doctor may not offer them or health insurance may not cover them.
For more information about uterine fibroids, call womenshealth.gov at 1-800-994-9662 or contact the following organizations:
National Institute of Child Health and Human Development Clearinghouse
Phone Number(s): (800) 370-2943
Internet Address: http://www.nichd.nih.gov/publications/pubs.cfm
American College of Obstetricians and Gynecologists (ACOG) Resource Center
Phone Number(s): (202) 863-2518 (Publications requests only)
Internet Address: http://www.acog.org/
Center for Uterine Fibroids
Phone Number(s): (800) 722-5520 (Ask operator for 525-4434)
Internet Address: http://www.fibroids.net
National Uterine Fibroids Foundation
Phone Number(s): (800) 874-7247
Internet Address: http://www.nuff.org/
All material contained in the FAQs is free of copyright restrictions, and may be copied, reproduced, or duplicated without permission of the Office on Women's Health in the Department of Health and Human Services; citation of the source is appreciated.
This FAQ was expert reviewed by:
Steve Eisinger, MD, FACOG
Professor of Family Medicine
Professor of Obstetrics and Gynecology
University of Rochester School of Medicine and Dentistry
Give us feedback on this page |
Content last updated May 13, 2008.
This site is owned and maintained by the Office on Women's Health
in the U.S. Department of Health and Human Services.
You may need to download a free PDF reader to view files marked with this icon.
Home | Site index | Contact us
Health Topics |
Tools |
Organizations |
Publications |
Statistics
| News | Calendar | Campaigns | Funding Opportunities
For the Media |
For Health Professionals |
For Spanish Speakers (Recursos en Español)
About Us |
Disclaimer |
Freedom of Information Act Requests |
Accessibility |
Privacy