Fibroids are non-cancerous growths that develop in or around the uterus. They are made up of muscle and fibrous tissue and can vary in size, from as small as a pea to as large as a melon. Fibroids are also known as uterine myomas or leiomyomas. They are most common in women between the ages of 16 and 50, during their reproductive years when estrogen levels are at their highest. Fibroids can be asymptomatic, and many women may not even know they have them. However, when they do cause symptoms, they can include heavy or painful periods, abdominal or lower back pain, frequent urination, constipation, and pain or discomfort during sex. The exact cause of fibroids is not known, but studies suggest that there may be a genetic component. Fibroids are almost always benign, but in rare cases, they can cause complications during pregnancy or infertility. Treatment options for fibroids depend on the size, location, and severity of symptoms and can range from medication to surgery.