Older Maternal Age Found to Up Risk of Autism in Offspring
by -- Jane Parry Updated: Feb 25th 2010
THURSDAY, Feb. 25 (HealthDay News) -- Women who give birth over the age of 40 are more likely than their younger counterparts to have a child with autism, but the father's age only affects the odds of autism when the mother is under 30, according to a study published online Feb. 8 in Autism Research.
Janie F. Shelton, of the University of California in Davis, and colleagues analyzed data from California state birth files on 4,947,935 singleton births from 1990 to 1999, of which 12,159 were subsequently diagnosed with autism. They looked at the odds of having a child with autism according to the age of the mother and the father.
Women who gave birth at 40 and above were 51 percent more likely to have a child with autism than their 25- to 29-year-old counterparts, and 77 percent more likely to do so than the under-25 mothers, the data showed. However, among couples where the father was 40 and over and the mother was under 30, the odds of having offspring with autism were 59 percent higher than in couples where the father was aged 25 to 29 and the mother under 30, the researchers found.
"These findings suggest the increased risk associated with older fathers is overwhelmed by the maternal age effect in the later years of fertility," the authors write. "Alternatively, these findings may suggest a different mechanism for paternally versus maternally mediated age effects."
