Here is some information from the NIH about gestational diabetes. http://www.nichd.nih.gov/health/topics/gestational_diabetes.cfm
But the short answer is that babies born to mothers with gestational diabetes are at risk for obesity, diabetes and impaired glucose tolerance as they get older. The good news is that by staying active and at a healthy weight you can help your children to prevent or delay diabetes. So one of the most important thing you can do for your baby and your family is to establish habits that support a healthy lifestyle. A good resource for doing that is: www.yourdiabetesinfo.org/diabetes-healthsense.