This is a crazy question but I'm currently 5'3 170lbs and a type 2 insulin dependant diabetic. I'm 15 months post op RNY. Since I'm going to have to be extremely careful with my diet because of the diabetes do you guys think I'm going to gain much weight. I know that's hard to predict, I'm almost wondering if I'll lose weight, and if I do is that bad for the baby? Anyone one else in my predicament and how much did you gain. Also since I have excess skin around my belly will I likely stretch even that and have new stretch marks?

Most women, even the diabetics on the board, gain weight.  It is hard to predict how much, and a lot depends on diet/exercise.  I think you'll find you can eat a lot more when you're pregnant than when you aren't.  Some women do lose weight, but mostly if that happens they lose for the first trimester, then start gaining.  There are some women who have a net loss, but those are usually the women who were very, very early out from surgery and still had a lot to lose. 

I also had excess skin, and didn't get any new stretch marks with either pregnancy.
Good luck.

 I had some excess skin around my belly and I've only have two new stretch marks (they are on my hips.) And I can't exercise at all I'm on strict bedrest. Most people say I am just now starting to look pregnant and I'm 27 weeks tomorrow.