But some mums find the standard 2D scans disappointing when all they see is a grey, blurry outline. This is because the scan sees right through your baby, so the photos show her internal organs. With 3D and 4D scans, you see your baby’s skin rather than her insides. You may see the shape of your baby’s mouth and nose, or be able to spot her yawning or sticking her tongue out.

3D and 4D scans are considered as safe as 2D scans, because the images are made up of sections of two-dimensional images converted into a picture. However, experts do not recommend having 3D or 4D scans purely for a souvenir photo or recording, because it means that you are exposing your baby to more ultrasound than is medically necessary. Some private ultrasounds can be as long as 45 minutes to an hour, which may be longer than recommended safety limits.

3D and 4D scans may nonetheless provide more information about a known abnormality. Because these scans can show more detail from different angles, they can help in the diagnosis of cleft lip. This can help doctors to plan the repair after birth.

3D scanning can also be useful to look at the heart and other internal organs. As a result, some fetal medicine units do use 3D scans, but only when they’re medically necessary.