What Are Uterine Fibroids?

Each year 200,000 women are affected by uterine fibroids. These masses are typically benign, and can grow on the inside, outside or within the wall of the uterus.

The cause of fibroids is not well understood, but the hormone estrogen seems to make them grow. Because the highest levels of estrogen are produced during a women’s childbearing years, many women are affected in their 30’s and 40’s. Fibroids are rare in women under 20, and typically stabilize in size and shrink after menopause.


A family history of fibroids, obesity, or early onset of puberty can increase the risk of a woman developing uterine fibroids. Many women who have fibroids are not aware of them and not all fibroids require intervention. Uterine fibroids do not need to be removed if they are not causing pain, bleeding, or interfering with fertility. For those women who do have symptoms, fibroids can be hard to live with and may require management through a medical or surgical procedure.