See expert ASAP. Before trying to conceive (ttc), see an expert--perinatologist or mfm subspecialist or endocrinologist with experience with diabetes in pregnancy. Have tests of heart, kidneys, eyes, hgba1c. Improve glycemic control with ada diet, exercise, Insulin under md care. Take folate (folic acid). When stable, then try. Let doctors know as soon as you think you might be pregnant. This is best approach for you and baby.
See your doctor. Diabetes is much safer in pregnancy if it is under good control before you get pregnant. Some of the diabetic medicines are not safe in pregnancy. It is always best for a diabetic woman to see her doctor before she considers pregnancy.