OT--interesting article on autism

[Guest guest]

http://www.nationalpost.com/home/story.html?f=/stories/20011123/800351.html

November 23, 2001

Stressful pregnancy may raise autism risk

Fetuses found to be vulnerable in 24th to 28th week

Margaret Munro

National Post

Pregnant women who suffer a major stressful event --

such as the death of a loved one, loss of a job or a

long-distance move -- seem to have a greater chance of

having a child with autism, researchers say.

Fetuses 24 to 28 weeks old appear to be particularly

vulnerable to the ill effects of maternal stress,

which may deform their developing brains, according to

a study led by Beversdorf, a neuroscientist at

Ohio State University Medical Center.

He and his colleagues charted the stress experienced

by 500 women during their pregnancies. They found the

188 mothers in the group who had children with autism

experienced much more major stress during the 24th

through 28th weeks of their pregnancy than those with

normal children.

Stress levels during pregnancy for the mothers of

children with autism were nearly twice those of other

mothers in the study. Dr. Beversdorf says the results

indicate there is much more than genes at work in the

baffling disorder.

" Researchers have been examining the genetic component

of the disease for years, but there is now evidence

through this study that autism is also linked to

external factors, such as prenatal stress, " says Dr.

Beversdorf, who issued a statement on the findings

this week after reporting the results at the annual

meeting of the Society for Neuroscience in San Diego.

Autism is a neurological disorder that usually appears

before a child's third birthday.

Autism is being diagnosed in increasing numbers among

children in the industrialized world. About one in

1,000 children has autism, using the term's most

narrow definition, but as many as one in 200 suffers

from autism-related conditions. The children typically

have trouble interacting and communicating with

others, suffer language delays and demonstrate

repetitive patterns of behaviour.

Parents and researchers have been searching for

explanations for decades. Environmental toxins and

childhood vaccinations have been implicated. And

scientists have linked more than a dozen different

genes -- many of them involved in brain development --

to autism.

Several findings " are difficult to reconcile with a

purely genetic cause of autism, such as the consistent

finding of an increased incidence of March birthdays

among autistic children, " Dr. Beversdorf and his

colleagues say. They also note that twin studies have

shown autism can occur in just one identical twin,

making it clear that more than genes is involved.

The researchers asked almost 500 mothers to recall

their stress levels during pregnancy. The study

included the 188 mothers of children with autism, 212

women who had normal children and 92 women who had

children with Down's syndrome, a neurological disorder

caused by chromosomal abnormality. Life-altering

events, such as the death of a spouse or losing a job,

qualified as " major stressors. "

The researchers found stress levels for the mothers of

children with autism were nearly twice those of the

other mothers. " A significant difference was detected

for the autism group, with a peak at weeks 24 to 28, "

they report. They say the timing seems to correlate

with the periods of development of the fetal

cerebellum -- a portion of the brain that is

structurally different in autistic children.

The findings are " certainly provocative " and worthy of

more research, says Bryson, a chair of research

for autism at Dalhousie University in Halifax.

Dr. Bryson's research suggests brain damage much

earlier in pregnancy -- toward the end of the first

month -- can cause autism. But she says there may be

many other factors, both genetic and environmental, at

work. Complicating things even more, the multiple

factors may be interacting.