What Are 3D And 4D Ultrasound Scans? - BabyCentre UK

What are the advantages of 3D and 4D scans?

It's natural to be really excited by the prospect of your first scan. But some parents 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 their internal organs. With 3D and 4D scans, you see your baby's skin rather than their insides (Shipp 2023). You may see the shape of your baby's face, mouth and nose, or be able to spot them yawning or sticking their tongue out (FDA 2020).

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3D and 4D scans may 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 (Ji et al 2021, Shipp 2023). This can help doctors to plan treatment to repair a baby’s cleft lip after birth. 4D scanning can also be useful to look at the heart and other internal organs (Shipp 2023). As a result, some NHS fetal medicine units do use 4D scans, but only when they're medically necessary.

Are 3D and 4D scans safe?

3D scans are considered as safe as 2D scans, because the images are made up of sections of two-dimensional images converted into a picture. 4D scans, however, use real-time moving 3D images and these expose your baby to higher energy outputs than 2D scans (RCOG 2015).

For safety reasons, 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 (BMUS nd, ECMUS 2012, FDA 2020). Most NHS ultrasounds take about 20 minutes and rarely last longer than 40 minutes, which is within safe limits even in early pregnancy (RCOG 2015). Some private ultrasounds may be longer than this.

There’s no evidence to suggest that the scans aren’t safe, and most parents-to-be gain reassurance from them. Nonetheless, any type of ultrasound scan should only be performed by a trained professional, for as short a time and at the lowest intensity, as possible (ECMUS 2012, FDA 2020, RCOG 2015).

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Where can I get a 3D or 4D scan?

If you’d like a 3D or 4D scan you’ll probably need to arrange it privately, and pay a fee (SoR 2021). The clinic may also give you a recording of the scan on DVD, though this is likely to cost extra. Some clinics will charge you even more for high definition footage of your baby. This may be called 4D HD Live and gives even clearer images of your baby. The special transducers and software required to do 3D and 4D scans are expensive. There are few clear medical benefits, and experts say they should only be done if there's a medical need (SoR 2021). So it's unlikely that these scans will replace normal 2D scans used for routine maternity care in the NHS.

When should I get a 3D or 4D scan?

If you decide to have one, the best time to have a 3D or 4D scan is when you're around 27 weeks to 32 weeks pregnant. Check with the clinic before your book. Before 27 weeks your baby has very little fat under their skin, so the bones of their face will show through. After 32 weeks, your baby's head may go deep down in your pelvis, so you may not be able to see their face. Experts also say that the second half of pregnancy is a safer time to have a 3D or 4D scan as your baby is at a less critical stage of development than the first and early second trimester (RCOG 2015).

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If you're pregnant with twins or more, it's best to have a 3D or 4D scan earlier rather than later, when you're about 24 weeks to 27 weeks pregnant, so you can get a clearer view of each baby.

Advertisement | page continues belowIf the placenta is at the front of your womb (uterus), known as anterior placenta, you'll get the best images of your baby if you wait until about 28 weeks.

Will I see my baby’s face in a 3D or 4D scan?

It's natural that you'd like to see your baby's face on the scan. But sometimes it's not possible, depending on how they’re lying. If they’re lying facing outwards, with a good pool of amniotic fluid around their features, you should be able to see their face clearly. But if they’re facing your back, their head is far down in your pelvis, or there's not much fluid around them, you won't see much. The same applies if you have a lot of tummy fat (Shipp 2023).

The sonographer may ask you to go for a walk, or to come back in a week, when your baby may have moved to a better position. If it's not possible to get good views of their face, you may be able to see their fingers and toes instead (FDA 2020).

Advertisement | page continues belowSome private providers may offer you a free repeat scan if you can’t see your baby’s face. However, others will advise you of the limits of ultrasound and may not offer to repeat the scan. Check the company's policy before parting with any money. Find out more about other types of ultrasound in pregnancy.