what age is high risk for down syndrome?
But there is one key risk factor for Down syndrome: maternal age. A 25-year-old woman has a 1 in 1,200 chance of having a baby with Down syndrome; by 35, the risk has increased to 1 in 350; by age 40, to 1 in 100; and by 49, it's 1 in 10, according to the National Down Syndrome Society.