3D scans are the 3 dimensional scanning of the baby. And the 4 D scan are the moving 3D images of your baby. Time is the fourth dimensions in the 4D tests. These 3D and 4D scans cannot be done often because the ultrasound may harm the child. One time tests are safe but overdoing it can harm the child. Earlier the 2D scans were not that exciting as it just gave the black and white blur images.

But these sonographies can help detect any kind of birth defects if there be any.