Uterus - The organ in a woman in which the embryo/fetus grows; also called the womb.

Ultrasound (sonogram) - A test which uses sound waves to produce images of internal structures. During pregnancy it is used to evaluate the health and growth of the fetus.

Umbilical cord - The structure that connects the fetus's bloodstream to the placenta, and hence to its mother's bloodstream. The cord removes waste products and carbon dioxide from the fetus and brings oxygenated blood and nutrients from the mother to the fetus.