Uterine fibroids, also known as uterine leiomyoma, myoma, fibromyoma, fibroleiomyoma, are benign smooth muscle tumors of the uterus. Most women have no symptoms while others may have painful or heavy periods. If they push on the bladder a frequent need to urinate may occur. They may also cause pain during sex or lower back pain. A woman can have one uterine fibroid or many of them. Occasionally fibroids may make it difficult to get pregnant although this is uncommon.