Fibroids are growths made of muscle and connective tissue that develop in or on the uterus. They are also called leiomyomas or myomas. Fibroids can vary in size and number, and some can be too small to see with the naked eye, while others can grow to the size of a grapefruit or larger. Fibroids can be located in different parts of the uterus, including the muscular wall of the uterus (intramural), the open space inside the uterus (submucosal), and the outside of the uterus (subserosal).

The exact cause of fibroids is not known, but studies suggest that genetics and prolonged exposure to estrogen may increase the risk of developing fibroids. Fibroids are most common in women between the ages of 30 and 50, and they are more common in African American women than in White, Hispanic, or Asian women.

Not all fibroids cause symptoms, but when they do, symptoms can include heavy menstrual bleeding, longer or more frequent periods, pelvic pressure or pain, frequent urination or trouble urinating, growing stomach area, and constipation. Fibroids can also affect fertility in a variety of ways, such as by blocking the uterus or fallopian tubes.

Treatment for fibroids depends on the size, number, and location of the fibroids, as well as the severity of symptoms. Small fibroids often dont need treatment, but larger fibroids can be treated with medications or surgery.