Narrator: This is Science Today. Expectant mothers who see very detailed pictures of their unborn child with 3-D ultrasound may have an advantage when it comes to pre-natal bonding and management. Thomas Nelson, a professor of radiology at the University of California, San Diego studied what effect these images had on mothers who smoked during pregnancy.

Nelson: While the results from that study were inconclusive for a number of reasons - not the least of which is most mothers know it's not good to smoke so they're a little embarrassed to participate in such a study making use of that, it was a very positive outcome in encouraging the fact that this is a very powerful way to help parents relate to their unborn child in a very positive way.

Narrator: 3D-ultrasound is much clearer than the sometimes fuzzy images produced by 2D-ultrasound.

Nelson: With the 3D-ultrasound images, you see a complete image of, for example, the entire face of the baby. It's not something that you need to be trained to recognize and then say 'oh yes, I understand.' It's intuitively obvious to you what you're looking at.

Narrator: For Science Today, I'm Larissa Branin.