The womb, or uterus, is a bundle of muscles. For unknown reasons, a part of this muscle sometimes forms a ball called a fibroid. These are called either uterine fibroids or fibroid tumors and are not cancerous. A fibroid can be as small as a pea or as large as a grapefruit.
Fibroids can be single or many.
They can be on the surface, in the middle of the muscle, or hang into the cavity of the womb. Usually, they slowly grow larger. At menopause they tend to shrink in size. It is estimated one out of three women over 30 years of age has fibroids. You may not know that you have fibroids because they often exist without any symptoms.