Fibroids are benign tumors that grow in or on the uterus. They can affect fertility and the chance of getting pregnant. Uterine fibroids are very common, with 20 to 80 percent of women developing noncancerous fibroids by age 50, and 30 percent of women between the ages of 25 and 44 have fibroid symptoms. This means that uterine fibroids are common in women of reproductive age.