Study Confirms Link Between Older Mothers and Autism

(AFP from NewsCore) – Women over 40 are nearly twice as likely to give birth to an autistic child than a mother under 30, researchers said Monday in a study that found more evidence of links between autism and maternal age.

The father's age had nearly no impact on the child's risk of autism unless the father is older and the mother is younger than 30, according to the 10-year study, which examined 4.9 million births in the 1990s.

"This study challenges a current theory in autism epidemiology that identifies the father's age as a key factor in increasing the risk of having a child with autism," said study lead author Janie Shelton.

She and her fellow University of California, Davis researchers examined data from all births in their state for a decade.

The study, published in the February issue of the journal Autism Research, found that the incremental risk of having an autistic child increased by nearly a fifth -- 18 percent -- for every five-year increase in the mother's age.

The risk for a woman over 40 to have a child later diagnosed with autism was 50 percent greater than for a mother aged between 25 and 29.

For mothers over 30, an older father did not appear to further increase the risk of autism, a pervasive developmental disorder of deficient social and communication skills, as well as repetitive and restricted behavior.

When the father was older and the mother was under 30, the child also had a high risk of developing autism, according to the study. Children born to mothers under 25 and fathers over 40 were twice as likely to develop autism as those whose father was between 25 and 29.

But that risk dissipated among mothers over 30.

The incidence of autism in the United States is estimated at between one in 100 and one in 110 children in the United States. Onset of the disorder begins prior to age three.