Since they aren't part of the standard prenatal tests, these scans are optional. Doctors usually perform 3D ultrasounds on women who request them. The concept around 3D ultrasounds is that it uses sound waves to create an image of the growing fetus. The image is then displayed on a screen. 3D ultrasounds create a three dimensional still picture of the growing fetus. 4D ultrasound scans will show a three dimensional image in motion. 4D allows [...]