Diabetes are greatly occur to diabetic person by several fold compare to a non-diabetic person. so there should be some medical explanations right. but i could not really find any relation between them. Help me please.

I am waiting for my second round of blood work to come back with the results as to whether or not i have gestational diabetes. My OB said she is pretty sure it will come back positive so while im waiting for the final results i want to make sure im not ingesting to many carbs. What is the suggested intake of carbs for someone with gestational diabetes and/or Type 2 diabetes?