News

18th May 2005

Difficult births may increase risk of autism

A difficult birth and a family history of mental illness may increase the risk of autism, according to US researchers.

The latest study by the Centers for Disease Control and Prevention is published in the American Journal of Epidemiology and is based on nearly 700 Danish children with autism.

The CDC team, working with colleagues at the University of Aarhus in Denmark, found children with autism were more likely to have had difficult births than other children of the same age.

This included breech births, premature births and problems immediately after delivery.

Experts already agree that there is a strong genetic link with the condition which affects more than 500,000 children in the UK.

However, it appears to be increasing more than would be expected for a genetic disorder and there is no evidence confirming that toxins, diets and other pathogens could be causing the increase.

The study says that parental psychiatric history was associated with the highest independent risk of autism.

But the researchers said that because none of these factors were present in the vast majority of the autistic children, other factors must also be important.

Diana Schendel from the CDC said, "At this point, we don't know for sure if these events are causes, but it certainly points us to look more closely at what happens during pregnancy as a possible opportunity for future prevention."

A spokeswoman from the National Autistic Society said "The causes of autism are still being investigated.

"Many experts believe that the pattern of behaviour from which autism is diagnosed may not result from a single cause.

"There is strong evidence to suggest that autism can be caused by a variety of physical factors, all of which affect brain development - it is not due to emotional deprivation or the way a person has been brought up."

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