4d baby scans are actually a pretty good name because aside from being a marketing pitch by obviously contrasting against the 2d nature of traditional ultrasoun

4d baby scans are actually a pretty good name because aside from being a marketing pitch by obviously contrasting against the 2d nature of traditional ultrasound, they actually are 4d if you include the time dimension - they can record clips of the baby. Under this scheme, traditional ultrasound would have to be called 3d, but nobody does this so it's a bit of a bait while still being technically accurate.