The older you are when you get pregnant, the more likely you are to have a chronic disease.

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

The older you are when you get pregnant, the more likely you are to have a chronic disease, such as high blood pressure or diabetes, that may be undiagnosed and can affect your pregnancy.