Uterine fibroids, also known as fibroid tumors, leiomyomas, fibromas or myomas, are benign (noncancerous) growths on the uterus. Uterine fibroids occur in 20 to 40 percent of all women older than 35 years of age.

Uterine fibroids are rubbery nodules that begin as irregular cells in the muscular layers of the uterus and grow slowly into tumor-like masses of connective tissue and smooth muscle.

Uterine fibroids may be as small as a pea or the size of a basketball. A woman can have one or many...