A uterine fibroid is a non-cancerous tumor of the uterus.
Fibroids can grow on the inside, outside, or within the wall of the uterus.
They range from small to large, and usually cause few if any problems. It's estimated that up to a quarter of all women over 30 have fibroids. They're believed to be present in nearly 40 percent of women over 40. After menopause, they tend to shrink and even disappear. The cause is unknown, but many experts suspect a link with the female hormone estrogen.