Types of Fibroids Uterine fibroids are growths that develop from the cells that make up the muscle of the uterus. The size, shape and location of the fibroids can vary. They may occur inside the uterus, on its outer surface or within the walls. Fibroids can range in size from pea-sized growths to large melon sized growths. As fibroids grow they can distort the inside as well as the outside of the uterus and can completely fill the pelvis and abdomen.
Fibroids can occur singly or in multiples of varying sizes.
Whether they will occur singly or in groups, fibroid growth is unpredictable. They may remain very small for a long time, suddenly grow rapidly, or grow slowly over a number of years. Although fibroids are quite common, little is known about what causes them. The female hormone estrogen seems to increase their growth. Symptoms of Fibroids Often fibroids, even large ones, produce no symptoms.