4D scanning: what is it and how does it work?

All you need to know about 4d scans

by Deborah Cicurel |

Who wouldn't want to see their baby in high-definition before he or she is even born? 4D scans are a popular method of giving parents a 3D moving image of their baby.

But how are they different from normal scans? Are they free? And are there any downsides? We’ve got everything you need to know about 4D scans here:

How does a 4D scan work and how is it different from a normal scan?

The scan can be one of the most exciting times of your pregnancy: you’ll get to meet your baby for the first time. But there are 2D, 3D and 4D scans – what’s the difference between them and how do they all work?

“Ultrasound scans, whether 2D, 3D or 4D, all work in the same way,” says Rachel Fitz-Desorgher, a midwife with 30 years’ experience in infant feeding, active births and working with parents.

The 4D scan is like a 3D scan but gives you a real-time three dimensional moving image.

“Quite simply, the scanning probe sends out high frequency sound waves which are  aimed at the baby. These sound waves bang into the baby and then bounce back again like an echo and are collected and turned into an image of the baby by a computer.

“A 2D scan (the one used most commonly in hospitals) sends the sound waves straight onto the baby from one angle and the echo can be built into a still two dimensional image.

“The 3D scans send waves from lots of different angles to give a still three dimensional image and the 4D scan is like a 3D scan but gives you a real-time three dimensional moving image.”

When should I have one?

According to Fitz-Desorgher, there’s no time you should or shouldn’t have a 4D scan, as they are not considered medically necessary, but are rather classed as “recreational”, “reassurance” or “keepsake” scans.

“It’s your choice whether or not to have one and so you can book when whenever you like,” she says. “However, to get the most out of a 4D scan, aim to be seen between 26 weeks and 30 weeks pregnant.

“At this stage, there should be enough fat on your baby that his or her face won’t look too bony and he or she won’t yet have started going down into the pelvis and disappearing from view.”

What will I be able to see?

When you book in for your 4D scan, you’d understandably be keen to see your baby’s face - but how much you will see will depend on which way your baby is facing.

“If your baby is facing out towards your belly button, you will see more than if he or she is facing towards your back,” says Fitz-Desorgher.

“Likewise if his or her head has already moved down into your pelvis, you might not see the face at all. Sometimes the baby is pressed up against the placenta and can look pretty odd or you might not get a full look.”

There are also other factors that can make it tricky to get a good view of your baby. Firstly, if you’re plump around your tummy, and secondly, if there isn’t much amniotic fluid around the baby.

However, even if you don’t get a great view, according to Fitz-Desorgher, you’ll still be able to see parts of your baby.

“Even if your baby is shy about showing their face, you will still be able to see fingers and toes wiggling and the arms and legs waving and kicking,” she says. “Unless your baby has their legs firmly crossed, you should be able to see the genitals.”

Plus, if you weren’t able to get a good view of your baby, you might be eligible for a second scan. “Some companies offer you a free second scan if the first one is not very good, and some do not, so check before you book,” she adds.

What are the benefits and downsides?

There are plenty of benefits of a 4D scan, but also a couple of downsides, so do your research before booking one.

Fitz-Desorgher says the benefits can include extra bonding with your baby not just for the parents, but also for the wider family.

“Because a 4D scan is done purely for your pleasure and not to look for problems, some couples find the experience more relaxing than the routine scans which are done for medical purposes,” she says.

“Some people say that seeing their baby so clearly helps them to bond before birth, which might be useful if a woman has been ambivalent about the pregnancy or unduly worried and so struggled to feel happy about the baby.

“Many clinics allow family members to come along for the scan and, if they can’t get there, they can enjoy looking at the DVD that is usually offered in the price of the scan.”

However, for all the benefits, there are a few downsides to bear in mind too.

“Because more detail is needed to build the moving image in a 4D scan, the scanning can take much longer - sometimes as much as 45 minutes,” she adds. “This means that the baby is exposed to the very intense sound waves for longer and more of the body surface is hit by the waves.

“Ultrasound waves cause vibrations and a slight heating in the body tissues which, when such an intense scan goes on for longer than is medically advised, might cause some harm. For this reason, the NHS has not approved the use of 4D scans or offer them for medical use.”

The NHS has not approved the use of 4D scans or offer them for medical use.

Apart from those concerns, Fitz-Desorgher says the scans could also worry parents depending on the baby’s position.

“Some couples don’t find the pictures reassuring at all, as if the baby is not lying in just the right position, he or she might look rather squished and bizarre,” she says.

“Remember that the photos in the glossy magazines are the very best ones. Your photos may not look anything like as cute.”

She also raises concerns that the scan could highlight something that could unnecessarily concern parents. “Although 4D scans are done for pleasure rather than medical reasons, sonographers do sometimes see things such as lumps or cysts,” she says.

“Although these are often harmless and may even disappear in time, parents become worried and then, when they discover that their NHS hospital is not willing to do a reassurance scan because of a worry caused by a 4D scan, they can spend the rest of the pregnancy fretting. Do think very hard before spending your money on a 4D scan.”

Can I get a 4D scan done on the NHS?

While you’ll be offered scans during your pregnancy on the NHS, these are not 4D.

“The simple answer to the question of getting 4D scans on the NHS is no,” Fitz-Desorgher says. “There are NHS hospitals that now offer 4D scans as ‘recreational scans’ but these are not free. The medical scans you will be offered during your pregnancy are not 4D.”

How much does a 4D scan cost?

If you’re adamant you want a 4D scan, make sure you do your research in advance to be sure of what your package includes.

“As with everything, cost varies from package to package, clinic to clinic and from town to city so do shop around,” Fitz-Desorgher advises. “Remember to ask if the price includes a DVD and whether or not you will be offered a free second scan if baby is shy first time. Expect to pay between £50 for a quick peek with no frills, to almost £300 for a top notch package with lots of photos, a DVD and other gifts.”

Rachel’s first book Your Baby Skin to Skin: Learn to Trust your Baby's Instincts in the First Year is out now. (£12.99 White Ladder Press).

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