During my research, what I discovered was that as women, we are born with a certain number of eggs that also age along with us. This means that with time, they too have had more exposure to infections, drugs, X-rays and other environmental contaminants. The risk of having a baby with Down Syndrome after age 35 is 1 in 365, compared to only 1 in 1,000 if you are 30 or 1 in 1,300 if you are 25 or younger, according to the American Pregnancy Association. Miscarriage is also more prevalent as you age, says the APA. Women under the age of 35 have about a 15% chance of miscarriage, increasing to a 20-35% chance when you are 35-45 years old and 50% if you are over 45.