Expectant parent' desire to see images of their unborn children has given rise to commercial companies offering keepsake ultrasound scans without medical supervision, often referred to as "boutique ultrasonography."

In a special report in this week's British Medical Journal, journalist Geoff Watts considers whether this non-medical use of the technique can be justified.

Improvements in ultrasound technology have transformed antenatal scans from two dimensional black and white images to 3D, 4D and even moving pictures of the unborn child. Expectant parents seeking a CD-ROM or a DVD of their scan can expect to pay £150-£250 (€230-380; $300-490).

The companies say that ultrasound has not been shown to cause any harm to mother or baby, but the US Food and Drugs Administration (FDA), the American Institute of Ultrasound in Medicine, and the French Academy of Medicine are among several official bodies that have reservations about such use of the technology. The British Medical Ultrasound Society does not have a specific policy on non-medical imaging, but is currently updating its guidance.

The FDA says: "Although there is no evidence that these physical effects can harm the fetus, public health experts, clinicians and industry agree that casual exposure to ultrasound, especially during pregnancy, should be avoided."

There are also concerns about how staff deal with the discovery of a fetal abnormality.

Some doctors offer keepsake images after they have performed ultrasound for medical reasons. The FDA takes a dim view of this, but the American Institute of Ultrasound Medicine deems it to be consistent with their ethical principles.

Beyond spreading a little happiness, the case for non-medical imaging relies principally on bonding: the sense of attachment between a mother and her unborn child, says Watts. The evidence that ultrasound images can foster this comes from 2D scans, but there is no evidence that 3D scans are more effective in enhancing maternal-fetal attachment.

The controversy over 3D and 4D imaging would be partially resolved if genuine medical benefit could be shown, he adds. Research is currently under way to find out if seeing the fetus in 3D might help spot abnormalities such as cleft lip. Early indications are that it may be useful but, for the moment, it is by no means self evidently beneficial.

Note: This article has been adapted from a news release issued by BMJ-British Medical Journal.