What are uterine fibroids?

Fibroid tumors are usually benign (non-cancerous) tumors found, most often, in the uterus of women in their 30's and 40's, although they occasionally develop on other organs which contain smooth muscle cells.

Fibroid tumors are solid tumors which are made of fibrous tissue, hence the name 'fibroid' tumor. Most often fibroids occur as multiple tumor masses which are slow-growing and often cause no symptoms.

The size of fibroids varies immensely among women and some are so small that a microscope is required to see them. However some women experience a single large fibroid tumor the size of a grapefruit or a fibroid which is so large it encompasses the entire abdominal area. Such large tumors can weigh as much as 50 pounds; the largest, reported, fibroid ever recorded weighed in at 140 pounds.

No one is sure why fibroid tumors develop, but some facts are quite clear-- they do not develop before the body begins producing estrogen during the onset of menstruation-- estrogen, such as in birth control pills and taken for menopausal symptoms, does cause fibroid tumors to grow and fibroid tumors will grow very quickly during pregnancy when the body is producing extra estrogen-- they often shrink and disappear after menopause when the body stops producing estrogen--a woman will almost never develop fibroid tumors after menopause.

The estrogen connection appears to be quite clear, although there are still some who doubt the role estrogen plays in the development of fibroid tumors because women with fibroids often have blood levels which reveal normal amounts of estrogen.