Fibroids are non malignant growths of uterine muscle that occur in up to one-third of all women. Fibroids may become larger during pregnancy, and typically shrink after menopause. They may cause excessive bleeding and pelvic pain or pressure. Fibroids are surgically removed in women of childbearing age when they become large and obstructive. Small fibroids are usually left alone. It is a myth that menopause will shrink fibroids. Everyone is different.