Here's the story from ABC:
The 4D ultrasound gives "realistic" pictures of your yet-to-be-born baby. It's so accurate you'll recognize your baby when it's born. Some doctors think of the 4-d as a "gimmick", saying it gives them little medical information, but the 4D may be finally proving it's "medical mettle."
The pictures are so good that mothers to be have sought these 4D ultrasound shots out in shopping malls just to have them for the baby albums. Patricia Diaz is a first time mom. She said, "I can see how he's gonna look when he's born. LBJ is one of the first Houston hospitals to have a 4D ultrasound and Patricia Diaz today got to see her little boy for the first time through the 4D technology. The pictures on this page show the difference between 2D and 3D ultrasounds. 4D is simply 3D that moves.
But the pictures have made 4D ultrasounds controversial in the medical world. Are they a toy or are they medically necessary? UT Houston OB-GYN Dr. Joan Mastrobattista says the 4D can find birth defects that other scans didn't show. Dr. Mastrobattista said, "If there's a cleft lip they can have an idea, ok that's what that looks like. It helps in some cases with parental bonding. In other cases it gives information, how do the hands look, how do the feet look is there an extra finger?