Ultrasound scans linked to foetal brain damage

Ultrasound scans on pregnant women can cause brain damage in their foetuses, causing some people to become left-handed and at higher risk of conditions ranging from learning difficulties to epilepsy, says a study.

Swedish scientists confirmed earlier reports on the effects of ultrasound with the most compelling evidence yet that unborn babies are affected by scanning, the Sunday Telegraph in London has reported.

The team compared almost 7000 men whose mothers had scans in the 1970s with 170,000 men whose mothers did not, looking for differences in the rates of left and right-handedness.

Men whose mothers had scans were significantly more likely to be left-handed, pointing to a higher rate of brain damage while in the womb.

Crucially, the biggest difference was found among those born after 1975, when doctors introduced a second scan later in pregnancy.

Such men were 32 per cent more likely to be left-handed than those in the control group.

The researchers said scans in late pregnancy were now routine in many countries. If the higher incidence of left-handedness reflected brain injury, "this means as many as one in 50 male foetuses pre-natally exposed to ultrasound is affected".

But Professor Juni Palmgren, of the Karolinska Institute in Stockholm and a member of the study team, urged people not to refuse ultrasound scanning.

"The risk of brain damage is only a possibility. But this is an interesting finding and needs to be taken seriously," he said.

In Britain, the rate of left-handedness has more than doubled, from 5 per cent in the 1920s to 11 per cent today. Researchers have estimated that only 20 per cent of this increase can be put down to the suppression of left-handedness among the older generation.

nzherald.co.nz/health