Fibroids: The Most Common Benign Tumor in Women

The uterus contains two types of tissue. The inner lining, called the endometrium, is the tissue that sheds each month during menstruation. Most of the uterus, however, is composed of muscle tissue or myometrium. Both tissues are capable of producing benign “tumors.” Overgrowth of the endometrium causes uterine polyps while overgrowth of the myometrium causes myomas—commonly called fibroids. The name is somewhat misleading as the tissue is not fibrous—it’s simply muscle tissue that grows in the shape of a sphere.

Fibroids occur in almost 25% of all women in the United States and are responsible for over 200,000 hysterectomies annually. They can occur anywhere in the uterus and can vary in size from the size of a pea to a watermelon!

Most women with fibroids don’t even know they have them. We find them frequently at the time of you annual visit during your ultrasound exam. Most fibroids occur in the body of the uterus. The one’s that lie in the uterine cavity – submucosal fibroids–are often the most troublesome as they tend to produce heavy vaginal bleeding. In the drawing above you can see a submucosal (“Sub- mew-koh-sal”) fibroid lies partly in the uterine cavity and partly in the muscle. The intramural (“in-trah-mew-ril”) fibroid shown above does not distort the uterine cavity and probably doesn’t produce any symptoms. The subserous (sub- sir-us”) fibroid typically distorts the outside of the uterine cavity. In general subserous fibroids produce few symptoms unless they get quite large or are located near the bladder. Fibroids located near the bladder can make you feel like you’re constantly running to the bathroom—urinary frequency.

What causes fibroids to grow?

The simple truth is that we’re just beginning to understand some of the reasons that fibroids grow. For most women the answer you’ll hear from your practitioner is “I don’t know!” We do know that fibroids are sensitive to estrogen. For instance, fibroids grow during pregnancy—sometimes dramatically. We also know that fibroids tend to get much smaller after menopause. In general, fibroids grow slowly but occasionally one encounters a woman whose fibroids grow rapidly.

The factors associated with the growth of fibroids include obesity, never having given birth to a child, early onset of menstruation and being of African American heritage.

What symptoms can fibroids produce?

Many fibroids produce no symptoms at all. For instance, the two subserosal fibroids shown in the drawing above would probably produce no symptoms and would require no treatment.

However, some fibroids do cause symptoms that include:

  • Heavy menstrual bleeding—typically, fibroids that produce heavy menstrual bleeding are located near the surface of the uterine lining or within the uterine cavity.
  • Urinary frequency—fibroids can dramatically increase the size of the uterus. Remember that the front wall of the uterus sits right behind the bladder. Therefore any enlargement at this point can reduce the bladder capacity and make you feel as if you have to go the bathroom frequently.
  • Fullness in the lower abdomen—in truth many women complain of a feeling of bloatedness and “fullness” in the lower abdomen yet most of them do not have fibroids. But a significantly enlarged uterus can cause a sense of fullness or bloodedness in the lower abdomen.
  • Painful intercourse—again, depending on the location of the fibroid(s) intercourse may become painful, especially during deep penetration.
  • Infertility—fibroids, especially those located, inside the uterine cavity are associated with infertility.
  • Reproductive problems—fibroids are sensitive to estrogen and progesterone; hormones made in abundance during pregnancy. Pregnancy is a time when fibroids can grow rapidly. Some of the complications of fibroids in pregnancy involve miscarriage and premature labor.

Can fibroids turn into cancer?

The likelihood that a fibroid may become cancerous is between 1/1000 and 1/10,000. Rarely are fibroids ever removed because of a concern that they are cancerous.

How do I know if I have fibroids?

Large fibroids can be detected on physical examination. Smaller ones are generally seen on ultrasound exam, CT scans and MRIs. Ultrasound, however, is quite accurate and cost effective and so this test is the one most often used.

Fibroids can also be detected on laparoscopy and hysteroscopy.

What if I have fibroids? What does it mean for me?

In most cases it means nothing for you. The vast majority of fibroids that we detect don’t produce any symptoms. They may be small and located in a portion of the uterus where they are not likely to produce any symptoms. You are less likely to need treatment for fibroids if:

  • You are over the age of 45
  • You are not suffering significant symptoms
  • They don’t seem to be growing if observed over a period of time
  • They are subserous or intramural

On the other hand you may need treatment if

  • You are having symptoms such as heavy vaginal bleeding
  • You are trying to conceive and have a significantly large fibroid (myoma)
  • It continues to grow over a period of months
  • You are younger than 35 years old