3D ultrasound scans are “still” colour pictures of your baby
in three dimensions. 4D ultrasound scans are moving 3D images
of your baby, with time being the fourth dimension. In other
words, 3D scans are similar to the coloured photos you see in
newspapers and magazines.
The ideal time to have a 3D or 4D scan is between 26 and 32
weeks. This is because, after 26 weeks the baby has more fat
beneath the skin, which gives a more ‘real-life” image of your
baby’s face/ body parts. After 32 weeks the baby may gets into
more difficult positions to scan so technically may be more
challenging. So sometimes, the face may not be well
visualised.
3D and 4D scans are not routine scans and will be more
expensive. They are known to give you a better bonding
experience. From a medical point of view, the benefits of 3D
and 4D scans over 2D scans appears to be limited to certain
clinical conditions.
2D, 3D and 4D scanning is not radiation and considered safe
for the fetus when performed by experts who understand the
physics of the ultrasound machine. Most of the current
ultrasound machines are approved by the FDA for fetal scanning
within limits.