Uterine fibroids can grow on the inside wall of the uterus, within the muscle wall of the uterus, or on the outer wall of the uterus. They can alter the shape of the uterus as they grow. Over time, the size, shape, location, and symptoms of fibroids can change.
As women age, they are more likely to have uterine fibroids, especially from their 30s and 40s through menopause (around age 50). Uterine fibroids can stay the same for years with few or no symptoms, or you can have a sudden, rapid growth of fibroids.
Fibroids are often first found during a routine pelvic exam. To double check, an ultrasound may be performed, either transvaginally or abdominally. A three-dimensional (3D) ultrasound or an MRI (magnetic resonance imaging) can also be used to find the fibroids, a process called fibroid mapping.
Fibroids do not grow before the start of menstrual periods (puberty). They sometimes grow larger during the first trimester of pregnancy, and they usually shrink for the rest of a pregnancy. After menopause, when a woman's hormone levels drop, fibroids usually shrink and don't come back.
Complications of uterine fibroids aren't common. They include: