What is the difference between a 2D, 3D and 4D ultrasound scan?

A 2D scan displays 2 dimensions – height and width.
A 3D scan displays 3 dimensions – height, width and depth (perception).
A 4D scan displays 4 dimensions – height, width, depth (perception) and movement.
A 4D scan is also referred to as “Live 3D” as the 4th dimension is time which is the actual movement of the baby.

A 4D Ultrasound Scan Video Clip