Both. I believed both should know what is going on. Good control is very important for you and your baby. Your internist know you very well but your OB is the expert in obstetric physiology and complications. Good luck.
Any high risk team. The decision for oral medication or Insulin should be made by a team that deals with type 2 pregnant diabetics routinely. Sometimes these teams are lead by knowledgable high risk ob/gyns sometimes by endocrinologists. It is often a team effort. Ask your ob/gyn what his/her experience and comfort level in following you is.
Nutrient based doc. Doctor thornalley in u.K has published that diabetics excrete masses of vitamin b1 in their urine and has treated diabetic complications with a derivative of the vitamin. This is because diabetes involves defective sugar metabolism. Find a doc who is familiar with this important work that has helped to show that the diabetes epidemic is related to poor nutrition.