Uterine Fibroids
On this page:
Uterine fibroids are tumors or lumps made of
muscle cells and other tissue that grow within the wall of the uterus.
Fibroids may grow as a single tumor or in clusters.
A single
fibroid can be less than one inch in size or can grow to eight inches
across or more. A bunch or cluster of fibroids can also vary in
size.
Return to top 
Most fibroids grow within the wall of
the uterus. Health care providers put fibroids into three groups based on
where they grow:
- Submucosal (pronounced
sub-myou-co-sul) fibroids grow just underneath the uterine
lining.
- Intramural (pronounced
in-tra-myur-ul) fibroids grow in between the muscles of the
uterus.
- Subserosal (pronounced
sub-sir-oh-sul) fibroids grow on the outside of the
uterus.
Some fibroids grow on stalks (also called
peduncles, pronounced ped-uncles) that grow out from the surface of
the uterus, or into the cavity of the uterus.
Return to top
Many women don’t feel any symptoms with
uterine fibroids. But fibroids can cause the following
symptoms:
- Heavy bleeding or painful periods
- Bleeding between periods
- Feeling “full” in the lower
abdomen—sometimes called “pelvic pressure”
- Urinating often (results from a fibroid
pressing on the bladder)
- Pain during sex
- Lower back pain
- Reproductive problems, such as
infertility, multiple miscarriages, and early onset of labor during
pregnancy
Return to top
Currently, we know little about what causes
uterine fibroids. Scientists have a number of theories, but none of these
ideas explains fibroids completely. Most likely, fibroids are the end
result of many factors interacting with each other. These factors could be
genetic, hormonal, environmental, or a combination of all three. Once we
know the cause or causes of fibroids, our efforts to find a cure or even
prevent fibroids will move ahead more quickly.
Return to top
In some cases, fibroids can prevent a woman
from getting pregnant through natural methods. However, advances in
treatments for fibroids and infertility have greatly improved the chances
for a woman to get pregnant, even if she has uterine
fibroids.
Researchers are still looking into what role, if any, uterine fibroids play
in infertility. Currently, though, there are few answers. One study’s results
suggest that only submucosal fibroids have a negative impact on fertility
(Pritts 2001), but these results are not yet confirmed. The relationship between
fibroids and infertility remains a very active research area.
Return to top
Hysterectomy is not the best option for
every woman with uterine fibroids. If a woman wants to have children, then
she would want to avoid this treatment. Likewise, if a woman isn’t showing
symptoms of uterine fibroids, or her fibroids are small, she may have
better results from pain medications or hormone treatments. Doctors are
also exploring less-invasive surgical treatments for fibroids that save
the uterus. See the What are the treatments for uterine fibroids?
section of this fact sheet for more information about less-invasive
treatments.
In some cases, though, a hysterectomy is the best
method of treatment. If you have uterine fibroids and are thinking about
having a hysterectomy, make sure you talk over all features of the
surgery with your doctor and your family. Having a hysterectomy means that
you will no longer be able to have children. This process cannot be
reversed, so be certain about your choice before having the
surgery.
Keep in mind that the physical scars of the procedure may
heal quickly, but some of the effects of hysterectomy are long-lasting.
You may want to talk to women who have had the procedure before you decide
to have your surgery. Many health care centers, women’s clinics, and
hospitals offer support groups for women who have had, or are in the
process of having a hysterectomy.
Return to top
Most of the time, fibroids grow in women of childbearing age. Research studies
estimate that doctors diagnose up to 30 percent (Newbold et al 2000) of women
of childbearing age with uterine fibroids; but, because some women show no
symptoms of fibroids, as many as 77 percent of women of childbearing age could
have the condition, without knowing it (Cramer & Patel 1990). We don’t
know exactly how many new cases of fibroids occur in a year, nor do we know
how many women have fibroids at any one time.
There have also been reports of rare cases in which
young girls who have not yet started their periods (pre-pubertal) had
small fibroids.
Researchers now recognize several risk factors for
uterine fibroids.
- Current statistics place African-American
women at three-to-five times greater risk than white women for
fibroids.
- Women who are overweight or obese for
their height (based on body mass index or BMI*) are also at slightly
higher risk for fibroids than women who are average weight for their
height.
- Women who have given birth appear to be
at lower risk for uterine fibroids.
But, because we don’t know what causes
fibroids, we also don’t know what increases or reduces their
growth.
Return to top
Unless you start to have symptoms, you
probably won’t know that you have uterine fibroids.
Sometimes,
health care providers find fibroids during a routine gynecological
exam.
- During this exam, the health care
provider checks out the size of your uterus by putting two fingers of
one hand into the vagina, while applying light pressure to your abdomen
with the other hand.
- If you have fibroids, your uterus may
feel larger-than-normal; or, if you have fibroids, your uterus may
extend into places it should not.
If your health care provider thinks that you
have fibroids, he or she may use imaging technology—machines that create a
“picture” of the inside of your body without surgery—to confirm the
diagnosis. Some common types of imaging technology include:
- Ultrasound, which uses sound waves
to form the picture;
- Magnetic resonance imaging or MRI,
which uses magnets and radio waves to build the picture;
- X-rays, which use a form of
electromagnetic radiation to “see” into the body; and
- CT or “cat”-scan, which takes
x-rays of the body from many angles to provide a more complete
image.
Sometimes, health care providers use a
combination of these technologies.
Sometimes, however, the only way
to confirm the presence of uterine fibroids is through
surgery.
- Laparoscopy (pronounced
lapp-are-ah-skoe-pee)—In this procedure, the surgeon makes a small cut
into the abdomen, after inflating it with a harmless gas; then, using a
small viewing instrument with a light in it, the doctor can look for
fibroids.
- Your health care provider may suggest a
procedure called a hysteroscopy (pronounced hiss-tur-ah-skoe-pee), which
involves inserting a camera on a long tube through the vagina directly
into the uterus to see the fibroids.
Keep in mind that because these are surgical
procedures, you will need time to recover from them. However, the amount
of recovery time you’ll need may vary.
Return to top
Health care providers consider a number of
things when recommending treatment for fibroids, including:
Does
the woman have symptoms of uterine fibroids?
Does she want to
become pregnant?
How large are the fibroids?
What is the
woman’s age?
If a woman has uterine fibroids, but shows no
symptoms or has no problems, she may not need any treatment. The
provider will check the fibroids at a woman’s routine gynecological exam
to see if they have grown.
If a woman has pain now-and-then or
feels mild symptoms, her health care provider may suggest pain
medication, ranging from over-the-counter remedies to strong
prescription drugs.
If a woman has many symptoms or feels pain
often, she may benefit from medical therapy—that is, therapy using
certain medications rather than surgery. Keep in mind that many
medications have side effects, some of them serious.
- One way to reduce symptoms of uterine fibroids is using one of a
group of hormones called gonadotropin releasing hormone agonists
(GnRHa). These hormones block the body from making the hormones that
cause women to menstruate or have their periods. If you have symptoms,
have health conditions that make surgery less advisable, and are near
menopause or do not want children, you may receive GnRHa therapy to
treat your fibroids.
- Antihormonal agents, like mifepristone, also slow or stop the
growth of fibroids.
- Medical therapy is often used before a woman has surgery for her
fibroids.
- This therapy offers only temporary relief from the symptoms of
fibroids; once a woman goes off the therapy, her fibroids often grow
back.
If a woman has moderate symptoms of
fibroids, surgery may be the best form of treatment.
- Myomectomy removes only the
fibroids and leaves the healthy areas of the uterus in place. This
procedure can preserve a woman’s ability to have children.
- Hysterectomy is used when a
woman’s fibroids are large, or has heavy bleeding, and she is either
near or past menopause, or doesn’t want children. Hysterectomy is the
only sure way to cure uterine fibroids. In general, recovery time from a
hysterectomy is one to two months. Health care providers now have
hysterectomy options that differ in how invasive they are.
- Abdominal hysterectomy is a
procedure that involves a cut into the abdomen to remove the
uterus.
- Vaginal hysterectomy is less
invasive because the doctor reaches the uterus through the vagina,
instead of making a cut into the abdomen. This procedure may not be an
option if the fibroids are very large.
Currently, researchers are looking into
other methods of treating uterine fibroids. Keep in mind that these
methods are not yet standard treatments for uterine fibroids, which means
your health care provider may not offer them, or your insurance company
may not pay for them. But, it’s possible that research to confirm the
safety and effectiveness of these “experimental” treatments will advance
our ability to treat uterine fibroids. These developing treatments
include:
- In cryomyolysis (pronounced
cry-oh-my-oh-lie-sis), the health care provider puts a freezing agent
directly on the fibroids to make them shrink.
- Uterine Artery Embolization (UAE)
cuts off the blood supply to the uterus and the fibroids, which makes
them shrink. Recovery time for UAE is much shorter than for
hysterectomy. But, this option limits a woman’s ability to have
children.
Return to top
Uterine fibroids are not cancerous. Fibroids are not associated with
cancer; they rarely develop into cancer (in less than 0.1 percent of cases).
Having fibroids does not increase your risk for uterine cancer (Levy et al
2000).
Return to top
For the most part, fibroids stop growing or
shrink once a woman passes menopause. However, this is not the case for
all women. Some studies suggests a relationship between hormone
replacement therapy or HRT, used to reduce the symptoms of menopause, and
uterine fibroids, but the nature of this relationship is still unclear
(Schwartz et al 2000). More research is needed in this area.
Return to top
