3D ultrasound is a painless, advanced imaging test that produces a 3-dimensional picture of internal body structures using sound waves that bounce off of an organ, fetus, tumor or other structure within the body. It may be provided as an elective test for expectant mothers in order to allow them to see their baby’s facial features as well as to determine the baby’s gender. It can also be used to detect physical abnormalities in a fetus such as a cleft palate. The difference between traditional 2D ultrasound and the 3D version is that, in the second instance, sound waves are directed at the point of interest from multiple angles rather than simply straight on, allowing for greater accuracy and detail in the picture. A 4D ultrasound is much like a 3D ultrasound, but is able to produce moving images for a “real time” video effect. In the case of obstetric ultrasonography, 3D and 4D ultrasound tests can achieve the best visuals if administered when the baby is between 26 and 30 weeks of gestation.