Glossary — U

Ultrasound imaging uses high-frequency sound waves — far above what the human ear can detect — to create real-time images of internal structures. It is widely used to examine the breast, abdomen, pelvis, heart, and blood vessels, and it is the standard imaging tool in obstetrics for monitoring pregnancy.

Uterine cancer refers to malignant tumors that develop in the uterus. The vast majority are endometrial cancers, arising in the endometrium — the inner lining of the uterus — and they are the most common gynecologic cancer in the United States. Less common is uterine sarcoma, which develops in the muscle wall of the uterus.

Uterine fibroids are noncancerous tumors made of muscle and fibrous tissue that grow in or on the walls of the uterus. They are extremely common — affecting up to 80% of women by age 50 — and many women have them without ever knowing. When symptoms do occur, they may include heavy periods, pelvic pressure, or frequent urination.