Fibroids also called leiomyomas or myomas are tissue tumors or masses arising in uterine muscle that can distort the uterus. Although they are called tumors or masses, they are benign and are not cancer. Fibroids are very common, as many as three out of four women may have them during their reproductive years. They can cause pain and bleeding, but they do not always cause symptoms as many women do not even know they have them unless found during a gynecologic examination. Fibroids may also be associated with infertility and recurrent miscarriage.
No one knows why fibroids occur in some women but not in others. One possibility is that a muted or altered gene causes smooth muscle cells in the uterine muscle to grow forming a firm mass or multiple masses. Although the exact cause for their growth is unknown, we do know that they grow in response to estrogen that is naturally made by a woman’s body during her reproductive years. Some experts have suggested that the real cause of fibroids could be a combination of genetic, hormonal, and environmental factors. If your mother or other close female relative has had fibroids, your risk of getting them is higher. Obesity may also increase your risk. Women who have given birth may have a lower risk for fibroids.