Women who wait until their 40s to have a baby are much more likely to have a child with autism, say researchers.
For every 5-year increase in a mum-to-be’s age it seems her chances of having an autistic child rise by 18%. For a woman in her 40s, the risk is 50% greater than that of a mum-to-be aged 25 to 29, and 77% higher than that of a mum under 25.
While it was already known that older parents had a greater chance of having an autistic child, it wasn’t known if the mum’s age or the dad’s age was the most important factor. The study concluded that the dad’s older age is only a factor when the mum is young.
The figures come after researchers looked at almost 5 million births in California, from 1990 to 1999.
“We still need to figure out what it is about older parents that puts their children at greater risk for autism and other adverse outcomes, so that we can begin to design interventions,” said researcher Irva Hertz-Picciotto, professor of public health sciences.