International Federation of Gynecology and Obstetrics

Scientists have found that a higher maternal age increases the risk of a child developing autism in later life.

The joint study by a team at the Karolinska Institutet in Sweden and King's College London found that children of mothers older than 35 had a 30 per cent increased risk of developing autism, while children of mothers under the age of 20 had the lowest risk.

Researchers analysed 25,687 cases of autism spectrum disorder against 8.6 million control subjects in past studies and found that the association between maternal age and the condition was stronger in male children and those infants who were diagnosed in the more recent past.

Sven Sandin, lead researcher, said, "The study makes us confident there is an increased risk for autism associated with older maternal age, even though we do not know what the mechanism is."

He explained that the study had been controlled for paternal age, which is an independent risk factor.

Posted by Martine Ward