I agree with Annette and Saffy. I brought it up with my endo before my husband and I ever started talking about marriage. For many of the women here in the Oh Baby group, bringing our A1c’s into the target range and getting everything in check has taken 1-2 years (or more!). It took me about 2 years to bring my A1c from the 8s to the 6s and to get all my bad eating/testing/insulin/treating habits in check. I just gave birth two weeks ago to a healthy little girl. And my A1c stayed in the 5s throughout my pregnancy.
My CDE and my endo helped me start a regimen that would treat me like I was pregnant well before I started trying to conceive. That way, in my CDE’s words, “the only thing we add is the baby.” I had to keep my pre- and post-meal numbers in a healthy pregnancy range and begin eating in a more measured way. That brought my A1c where it needed to be and then I got the green light. It took me another 9 months to conceive, but I kept up the great habits. By the time the baby was actually on board, taking great care of my diabetes had become routine again!
So yeah, start voicing your goals now. Your team will certainly help you get where you need to be. As for a nutritionist, my CDE switched me to another CDE in our office who specialized in nutrition once I actually became pregnant. I saw my OB at 9 weeks pregnant and my perinatalogist for the first time at 13 weeks. But my regular team was fine to get my started.