Uterine fibroids are tumors made of connective tissue and smooth muscle. They grow slowly within the wall of the uterus or attach to the uterine wall. The uterus is the muscular organ at the top of the vagina.
Babies develop in the uterus, and menstrual blood comes from the uterus.
A uterine fibroid may be as small as a pea or as large as a grapefruit. As the fibroid grows, the uterus may become deformed or pushed aside. When the uterus is deformed or blocked by a growth, the resulting pressure may cause symptoms in the bladder or intestine, such as increased urination, constipation, or pain. Most fibroids are noncancerous, but in some rare cases they may become cancerous. Other terms used for a uterine fibroid are leiomyoma or myoma of the uterus.