BBC NEWS Americas Africa Europe Middle East South Asia Asia Pacific Arabic Spanish Russian Chinese Welsh

 You are in: Health
Front Page 
UK Politics 
Background Briefings 
Medical notes 
Talking Point 
In Depth 

Commonwealth Games 2002

BBC Sport

BBC Weather

Sunday, 9 December, 2001, 04:22 GMT
Scans may 'cause brain changes'
Mother being scanned
Scientists have urged women not to refuse scans
Scientists in Sweden say they have found evidence ultrasound scans may cause brain changes in unborn babies after they found men whose mothers had tests were more likely to be left-handed.

They have concluded some male babies' central nervous systems might have been affected by the process, as a shift from right to lefthandedness is thought by some experts as indicate that some kind of damage has occurred.

I would urge people not to refuse ultra-sound scanning as the risk of brain damage is only a possibility

Professor Juni Palmgren
However as of yet there is no indication that harm was done to the babies through the scans, according to an article in a journal.

The implications of the study are to be discussed at an international meeting of scientists in Edinburgh this week.

A total of 7,000 men were studied whose mothers had scans in the 1970s and compared with 172,000 men whose mothers had not had scans.

Increased risk

The study suggested scanning produced an extra three left-handed babies per 100 births.

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

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

The paper in the journal Epidemology concluded there were some possibilities the ultrasound had affected the brain.

However remote the risk, this was serious enough to merit concern.

The researchers warned: "The present results suggest a 30% increase in risk of left-handedness among boys pre-natally exposed to ultrasound."

"If the association reflects brain injury, this means as many as one in 50 male foetuses pre-natally exposed to ultrasound are affected."

However the research found no harm to the babies had been demonstrated.

Prof Juni Palmgren, of the Karolinska Institute in Stockholm, a member of the team, told The Sunday Telegraph: "I would urge people not to refuse ultra-sound scanning as the risk of brain damage is only a possibility - but this is an interesting finding and needs to be taken seriously."

Later development

According to the Swedish scientists, the human brain undergoes critical development late into a woman's pregnancy.

The male brain is especially vulnerable because it continues to develop later than the female brain.

Many doctors believe ultrasounds, which are used routinely in late pregnancies, have saved countless lives and women should not be deterred from having an antenatal scan.

But Beverley Beech, chairwoman of the Association for the Improvements in Maternity Services, told the paper that women should be fully briefed on the risks of ultrasound and should avoid having scans unless they were essential.

The BBC's Jane Bennett-Powell
"Many doctors believe ultrasound has saved countless lives"
See also:

30 Jan 01 | Health
Scan reveals baby's face
02 Jan 01 | Health
US doctors offer full body scan
22 Jan 01 | Health
Worry over children's CT scans
27 May 00 | Health
Pioneering scan saves patient
23 Oct 00 | Latest News
Computer reveals '3D blood flow'
Internet links:

The BBC is not responsible for the content of external internet sites

Links to more Health stories are at the foot of the page.

E-mail this story to a friend

Links to more Health stories