Most expectant parents eagerly wait for the first ultrasound sight of the baby to be born in six months' time. It is often the first proof that all is well and the pregnancy is on track.
This is often the only view they get to see of their child until the day of the birth. However this is not enough for an increasing number of parents who are willing to pay hundreds of pounds for a clearer picture of their baby in the womb.
The primary purpose of the hospital scan is as a diagnostic tool, which is used to ensure the baby is growing at the correct rate and that the heart is beating. Unless called back for a second scan due to blood test results being abnormal parents have to go to private clinics for another look at their unborn child.
Terry Brown, clinic manager and sonographer of Healthcare Now, the first to offer the 4D scan says, "The technology used is extraordinary. Pregnancy is obviously a very special time for a woman, and quite often the excitement of having a memento of your baby moving before it's born can overtake the moment."
For a charge of £235, patients are given a half-hour diagnostic 2D scan and a half-hour 4D scan which produces moving pictures of a baby in the womb, sucking its thumb, yawning or even smiling. The images are then copied on to a DVD for the mum-to-be.
Terry says: "It's basically a nice scan for women to bond with their babies, to see the a real view of the arms, the face, the legs. It's the chance to see them opening their eyes, yawning or moving about. It also gives them reassurance.
"There are a lot of 4D scanning studios opening up throughout the country and this is what people obviously want."
However the firm stresses that this kind of scan is only for aesthetic purposes, and as such it will only offer the ultrasound following an all-clear 2D scan. Terry says, "People can get a whole diagnostic scan with us first followed by the 4D scan for aesthetic reasons. And if the diagnostic scan reveals any problems we put our referral links in place and tell them to go back and see their midwife. We wouldn't offer the 4D scan under those circumstances as it wouldn't be ethical."
"They love it. Even for us doing the scanning it has the wow factor. To see an unborn child waving or moving is amazing. And it looks much better in 4D. Sometimes the baby is in an awkward position but we always try our hardest to get the best pictures of the baby. It depends on the lie of the baby and the fluid around it."
Although ultrasound scans have been around for 30 years, debates about their use still continue in the medical community. In 1999 scientists in Dublin, carrying out research on mice, revealed that ultrasounds could be harming the cells of unborn babies, interfering with the delicate tissues in a growing foetus.
Indeed, the Royal College of Obstetricians and Gynaecologists recommends that "ultrasound in pregnancy be limited to medically-indicated procedures rather than for purely entertainment purposes".
A spokeswoman for the Royal College of Midwives, says: "The 3D and 4D scans should only be used as a medical necessity.
We're not against the scans and the way they work as they're very clear and good, but you should not be taking pictures because the safety of unnecessary scans is not clear. There's been no research as to whether this is safe. "For aesthetic purposes we do not recommend it. It should only be carried out for medical purposes only."