Medical names for a fibroid are leiomyoma, myoma, and fibromyoma. Fibroids are very common. They occur in 2 or 3 out of every 10 women over age 35. They occur most often in women between ages 30 and 50, although women in their 20s sometimes have them. It is common to have more than one fibroid. Some women may have as many as a hundred.
Fibroids can be as small as a pinpoint or as large as a coconut. They are usually round or oval in shape, like a ball or an egg. Their texture is firm, like an unripe peach. After puberty, the ovaries produce more hormones, especially estrogen. Higher levels of these hormones may help fibroids to grow, although exactly how this might happen is not understood by the scientific community. Fibroids can grow in response to stimulation by the hormone estrogen, produced naturally in the body. These growths can show up as early as age 20 and shrink after menopause when the body stops producing large amounts of estrogen.