Overview

What Are Uterine Fibroids?

What Are Uterine Fibroids?

Uterine fibroids (also called myomas or leiomyomas) are benign (noncancerous) tumors in muscle tissue that can change the shape or size of your uterus and sometimes your cervix. Fibroids occur when a single muscle cell in the wall of the uterus multiplies to form a noncancerous tumor. They start in the smooth muscle cells inside the wall of your uterus (myometrium). Fibroids usually occur in the form of multiple tumors, although single fibroids are sometimes possible.

Twenty percent of women in the reproductive years have fibroids.

Whether fibroids cause symptoms or require any type of treatment depends on their location and size in your uterus.

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What Causes Uterine Fibroids?

The exact cause of uterine fibroids is unclear, but there is evidence that it may be a combination of genetic, hormonal, and environmental factors. Researchers think that uterine fibroid tumors may form because of muscle cells inside the uterus that aren't normal. These cells then copy themselves quickly because of estrogen found in women's bodies.

Fibroids are usually found in or around the uterus, but they sometimes occur in the cervix. Fibroids within the uterus can be divided into three categories:

  1. subserous (located in the outer wall of the uterus);
  2. intramural (found in the muscular layers of the uterine wall);
  3. and submucous (protruding into the uterine cavity).

The only cure for fibroids that currently exists is to have a hysterectomy. During a hysterectomy, doctors remove the uterus.

Who Gets Uterine Fibroids?

Women who are close to menopause have the highest chances of developing fibroids. Women who are in middle age have been exposed to estrogen for years, which helps fibroids grow. Obese women also may have a higher chance of developing fibroids, in addition to women who have African American heritage. Doctors don't entirely understand why this is.

Other things that may increase your chances for developing uterine fibroids include the following:

  • Eating a diet with a lot of red meat
  • Having a family history of uterine fibroids
  • Having high blood pressure

Can Fibroids Decrease Fertility?

Uterine fibroids are common. Five to ten percent of infertile women have them. Certain types of fibroids are known to decrease fertility. They include fibroids that are inside the uterine cavity and very large fibroids (>6 cm in diameter) that are located within the wall of the uterus.

Because most women with fibroids will not be infertile, they and their partners should have a thorough evaluation to detect other problems that can decrease fertility. A fertility specialist can help determine if fibroids might be hampering their ability to conceive.

How do fibroids cause infertility?

There are several explanations for why uterine fibroids may reduce fertility:

  • Fibroids located above your cervix may change the normal position of your cervix. Your cervix is the vaginal opening to your womb. Fibroids may affect the number of sperm that can travel through your cervix.
  • Changes in the shape of your uterus can interfere with sperm movement.
  • Fibroids can block your fallopian tubes.
  • Fibroids may affect the blood flow to the uterine cavity where the embryo would implant.
  • Fibroids may cause changes in the uterine muscle that prevent sperm from moving.

Summary

Uterine fibroids are common and can affect fertility in many ways. They can affect ovulation, fertilization, and implantation. Treatment options vary, but treatment will help to address the gynecologic symptoms of fibroids and improve overall fertility.

Our fertility experts will work to address your individual situation, as the proper management of uterine fibroids will depend upon the severity of your symptoms.