Guest Author - Denise Howard, M.D., M.P.H.

Fibroids are tumors made of smooth muscle. The other term used to describe this tumor is leiomyoma. They can occur anywhere in the body; however the uterus is the most common and well known site. The tumors are typically not cancerous.

Fibroids are found in various sites of the uterus. Fibroids growing in the lining of the uterus are described as submucosal. If they are located within the body of the uterus the term intramural is used. Subserosal fibroids are located on the surface of the uterus. Subserosal fibroids can sometimes grow like a flower on a stalk in which case it is described as being pedunculated. They can range in size from 1 cm up to 15 centimeters or more. A woman’s uterus can contain 1 or multiple tumors. It isn’t unusual for fibroids to increase the size of the uterus to that of a term pregnancy.

A woman can have fibroids for many years before they are detected. They can sometimes be found on routine pelvic exam or a woman might present with problems that are eventually discovered to be caused by fibroids. Irregular periods or heavy periods are the most common problem that women with fibroids experience. Sometimes this can be so severe that a woman may develop anemia and need a blood transfusion. A woman may also develop symptoms of increasing abdominal size, constipation, urinary frequency and pelvic pressure. A markedly enlarged uterus can cause these symptoms. Severe pain with menstrual bleeding is another hallmark of uterine fibroids. Depending on their location fibroids can cause problems with infertility, preterm labor and growth restriction in a developing pregnancy. As fibroids enlarge the blood supply that they receive from the uterine vessels may be dramatically decreased. The fibroid can attach to other pelvic organs such as bowel and develop a new blood supply. It is described as being parasitic when this occurs. If it is unable to obtain an additional blood supply then it can infarct and die causing severe pain and fever. This process is called degeneration.

The chance of a woman having fibroids increases with age. The reported prevalence is approximately 13% in women but up to 35% in women over the age of 35. There appears to be some genetic connection in that the problem is more prevalent in family members of women with fibroids and in black women. Black women are 3 times more likely to have uterine fibroids compared to white women. See next weeks article for further discussion of uterine fibroids.