Extensive studies conducted over 35 years have found that ultrasound has not been shown to cause any harm to mother or baby.SIEMENS C5-2 http://www.philipsprobemachines.com/SIEMENS-C5-2.html These routine scans would be considered highly irresponsible if there were even a small risk to mother or baby. In 3D/4D scanning, exactly the same type and intensity of ultrasound is used as with conventional 2D scanning. 3D and 4D Ultrasound both utilize sound waves to look inside the body. The technology is similar to radar. A probe placed on the body emits sound waves into the body, listens for the return echo and generates an image. 4D ultrasound will be similar to a conventional scan in terms of sound exposure.