One of the questions that comes up a lot when discussing pregnancy scans is the difference between 3D ultrasound and 4D scans. You may hear both of these terms used, but the truth is that they actually refer to the same kinds of scans.
What is a 3D Ultrasound?
A 3D ultrasound is a very different experience to the usual scans you will have during pregnancy. 3D scans can only be performed between 26 and 32 weeks. At this stage, your baby is developed enough for us to get clear pictures but won’t have dropped down into the pelvis yet. The 3D scan is performed in the same way as your routine scans, using a very similar ultrasound machine. However, the software that processes the ultrasound date will layer lots of 2D images together in order to create a three dimensional image of your baby. The term 3D ultrasound comes from this difference from the usual “flat” pictures that you will see during most pregnancy scans. However, since the pictures will move in real time, just as during your 2D scans, this will sometimes be referred to as a 4D scan. The fourth dimension is time.
Why the Confusion?
The confusion over 3D and 4D ultrasounds occurs because both of these terms are equally valid
. Both describe the type of pictures you will see during your ultrasound scan. However, the companies producing the ultrasound software and the clinics offering these services did not sit down together to decide what to call them. Some started using the term 3D ultrasound while other thought that 4D scans were a better name. The important thing to remember is that it doesn’t matter whether you are being offered a 3D scan or a 4D one as the technology used and the images you see will still be the same.