Down's syndrome & maternal age

A woman's risk of having a baby with chromosomal abnormalities increases with her age.  

Down syndrome is the most common chromosomal birth defect, and a woman's risk of having a baby with Down syndrome is:

• At age 25 -  1 in 1,250
• At age 30 - 1 in 1,000
• At age 35 - 1 in 400
• At age 40 - 1 in 100
• At age 45 - 1 in 30
• At age 49 - 1 in 10