The primary purpose of a 3D ultrasound is for a woman to have an extremely clear image of her unborn child to see what it looks like or to determine the sex of the child. However, there are no direct medical benefits to a 3D ultrasound.

A 3d ultrasound displays tissues in three axis's. This allows for a more thorough representation of the fetus. A tri-focused emitter creates the image.

The most popular use of 3D ultrasound is to examine babies while they are still in the uterus. It allows doctors to get a really good look at the fetus and any potential problems.

time.

A 4D ultrasound is simply a 3D ultrasound that gets updated very rapidly making it look more like a live ultrasound than a static picture. The fourth dimension is time.