This risk goes up every year. If you get pregnant at age 25, your risk of having a baby with Down syndrome, for example, is about 1 in 1,250, according to the National Institutes of Health. At age 40, the risk is 1 in 100.

http://www.babycenter.com/404_what-are-the-risks-of-having-a-baby-if-im-35-or-older_3127.bc

Once you conceive, and you get past the first trimester miscarriages, you face a higher risk of conceiving a baby with a chromosomal problem. This risk goes up every year. If you get pregnant at age 25, your risk of having a baby with Down syndrome, for example, is about 1 in 1,250, according to the National Institutes of Health. At age 40, the risk is 1 in 100.