Uterine fibroids are noncancerous growths of the uterus that often appear during childbearing years. This aren't associated with an increased risk of uterine cancer and almost never develop into cancer.

Many women have uterine fibroids sometime during their lives. But most women don't know they have uterine fibroids because they often cause no symptoms. Your doctor may discover fibroids incidentally during a pelvic exam or prenatal ultrasound

Symptoms

• Heavy menstrual bleeding
• Menstrual periods lasting more than a week
• Pelvic pressure or pain
• Difficulty emptying the bladder
• Backache or leg pains
• Frequent urination

Fibroids are generally classified by their location. Intramural fibroids grow within the muscular uterine wall. Submucosal fibroids bulge into the uterine cavity. Subserosal fibroids project to the outside of the uterus.

Causes

• Hormones : Estrogen and progesterone, two hormones that stimulate development of the uterine lining during each menstrual cycle in preparation for pregnancy, appear to promote the growth of fibroids. Fibroids contain more estrogen and progesterone receptors than normal uterine muscle cells do. Fibroids tend to shrink after menopause due to a decrease in hormone production
• Genetic changes : Many fibroids contain changes in genes that differ from those in normal uterine muscle cells.
• Other growth factors : Substances that help the body maintain tissues, such as insulin-like growth factor, may affect fibroid growth.