only 4 to 6%, of which 90% is gestational debaites. I have had quite a few friends who have either had gestational debaites or have been borderline and have had to cut all sugar out and eat very very healthy. I am lucky that my insulin levels didn't remain low as my blood glucose rose. All of the normal stresses on the body during pregnancy require more insulin and if the body doesn't respond with increased insulin as the blood glucose is rising they end up having gestational debaites mellitus. The risk factors are, gestational debaites with a previous pregnancy, age, a previous pregnancy in which a child was 9 pounds or more at birth, a family history of type II debaites, and a couple more. Interestingly enough smoking doubles the risk of gestational debaites.I don't smoke myself, but if I did it sure would be scary to see how many medical issues double or more with being a smoker.