Im 35 weeks pregnant, and have gestational diabetes....?

My nutritionist told me that it was okay to eat sugar free jello, and other things that are sugar free as long as they are low in carbs. This is fine, except I was always told that I should avoid artificial sweeteners, she knows I am pregnant, so I just want to know, is it okay to have artificial sweeteners once in a while? I definitely wouldn't have it in excess, but can it harm my baby at this point in the pregnancy??