Uterine Fibroids: Just What Exactly Are They, and What Do I Need to Know
"Uterine fibroids (also
called leiomyomas or myomas) are benign growths of the muscle inside the uterus. They are not
cancerous, nor are they related to cancer. Fibroids can cause a wide
variety of symptoms, including heavy menstrual bleeding and pressure on the pelvis."
Uterine fibroids are extremely common. About 25% of women in their reproductive years have
noticeable fibroids. There are probably many more women who have tiny fibroids that are
Fibroids develop between the ages of 30-50. They are never seen in women less than 20 years
old. After menopause
if a woman does not take estrogen, fibroids shrink. It appears that African-American women are
much more likely to develop uterine fibroids.
Fibroids are divided into different types, depending on the location. Submucous fibroids are
found in the uterine cavity; intramural fibroids grow on the wall of the uterus; and subserous
fibroids are located on the outside of the uterus. Many fibroids are so large that they fit
into more than one category. The symptoms caused by fibroids are often related to their
Causes and symptoms
No one knows exactly what causes fibroids. However, the growth of fibroids appears to depend on
the hormone estrogen. Fibroids often grow larger when estrogen levels are high, as in
pregnancy. Medications that lower the estrogen level can cause the fibroids to shrink.
The signs and symptoms of fibroids include:
- Heavy uterine bleeding. This is the most common symptom, occurring in 30% of women who
have fibroids. The excess bleeding usually happens during the menstrual period. Flow may be
heavier, and periods may last longer. Women who have submucous or intramural fibroids are
most likely to have heavy uterine bleeding.
- Pelvic pressure and pain. Large fibroids that press
on nearby structures such as the bladder and bowel can cause pressure and pain. Larger
fibroids tend to cause worse symptoms.
This is a rare symptom of fibroids. It probably accounts for less than 3% of infertility
cases. Fibroids can cause infertility by compressing the uterine cavity. Submucous fibroids
can fill the uterine cavity and interfere with implantation of the fertilized egg.
- Miscarriage. This is also an unusual symptom of fibroids, probably accounting for only
a tiny fraction of the miscarriages that occur.
complications. Fibroids can greatly increase in size during pregnancy, because of increased
levels of estrogen. They can cause pain, and even lead to premature labor.
A health care provider can usually feel fibroids during a routine pelvic examination.
Ultrasound can be used to confirm the diagnosis, but this is not necessary.
Not all fibroids cause symptoms. Even fibroids that do cause symptoms may not require
treatment. In the majority of cases, the symptoms are inconvenient and unpleasant, but do not
result in health problems.
Occasionally, fibroids lead to such heavy menstrual bleeding that the woman becomes severely
anemic. In these cases, treatment of the fibroids may be necessary. Very large fibroids are
much harder to treat. Therefore, many doctors recommend treatment for moderately-sized
fibroids, in the hopes of preventing them from growing into large fibroids that cause worse
The following are possible treatment plans:
- Observation. This is the most common plan. Most women already have symptoms at the time
their fibroids are discovered, but feel that they can tolerate their symptoms. Therefore,
no active treatment is given, but the woman and her physician stay alert for signs that the
condition might be getting worse.
- Hysterectomy. This
involves surgical removal of the uterus, and it is the only real cure for fibroids. In
fact, 25% of hysterectomies are performed because of symptomatic fibroids. By the time a
woman has a hysterectomy for fibroids, she has usually endured several years of worsening
symptoms. That's because fibroids tend to grow over time. A gynecologist can remove a
fibroid uterus during either an abdominal or a vaginal hysterectomy. The choice depends on
the size of the fibroids and other factors such as previous births and previous
- Myomectomy. In
this surgical procedure only the fibroids are removed; the uterus is repaired and left in
place. This is the surgical procedure many women choose if they are not finished with
childbearing. At first glance, it seems that this treatment is a middle ground between
observation and hysterectomy. However, myomectomy is actually a difficult surgical
procedure, more difficult than a hysterectomy. Myomectomy often causes significant blood
loss, and blood transfusions may be required. In addition, some fibroids are so large, or
buried so deeply within the wall of the uterus, that it is not possible to save the uterus,
and a hysterectomy must be done, even though it was not planned. There are exceptions to
this, however. Sometimes, fibroids grow on a stalk (pedunculated fibroids), and these are
easy to remove.
- Medical treatment. Since fibroids are dependent on estrogen for their growth, medical
treatments that lower estrogen levels can cause fibroids to shrink. A group of medications
known as GnRH antagonists can dramatically lower estrogen levels. Women who take these
medications for three to six months find that their fibroids shrink in size by 50% or more.
They usually experience dramatic relief of their symptoms of heavy bleeding and pelvic
Unfortunately, GnRH antagonists cause unpleasant side effects in over 90% of women. The therapy
is usually used for only three months, and should not be used for more than six months because
the risk of developing brittle bones (osteoporosis
) begins to
rise. Once the treatment is stopped, the fibroids begin to grow back to their original size.
Within six months, most of the old symptoms return. Therefore, GnRH agonists cannot be used as
long-term solution. At the moment, treatment with GnRH antagonists is used mainly in
preparation for surgery (myomectomy or hysterectomy). Shrinking the size of the fibroids makes
surgery much easier, and reducing the heavy bleeding allows a woman to build up her blood count
Fibroids can cause problems during pregnancy because they often grow in size. Large fibroids
can cause pain and lead to premature labor
cannot be removed during pregnancy because of the risk of injury to the uterus and hemorrhage.
GnRH antagonists cannot be used during pregnancy. Treatment is limited to pain medication and
medication to prevent premature labor, if necessary.
Many women who have fibroids have no symptoms or have only minor symptoms of heavy menstrual
bleeding or pelvic pressure. However, fibroids tend to grow over time, and gradually cause more
symptoms. Many women ultimately decide to have some form of treatment. Currently, hysterectomy
is the most popular form of treatment.