What is the link between maternal age and Down syndrome?
Since Down syndrome is a chromosomal disorder caused by an error in cell division, the likelihood of such an error occuring increases with maternal age. This means that an older mother is more likely to give birth to a child with Down sydrome than her younger counterpart. However, overall, fewer older mothers have babies than younger ones. According to the National Association for Down syndrome, “80% of babies born with Down syndrome are born to women younger than 35. The average maternal age is 28 years old.” The likelihood of a woman under 30 years of age giving birth to a child with Down syndrome is less than 1:1000, but increases the older the woman gets (see chart below), with an incidence of about 1:112 at 40 years of age. An annual occurence of Down syndrome of about 9% is seen in women 35 years of age or older, but about 25% of babies with Down syndrome are born to women in this age group. 20-25% of babies conceived with Down syndrome survive past birth. Notification rates to t
