Thoughts on soda

I was never really a big soda drinker but since I've been pregnant I will have some kind of soda and cut it in half with seltzer. I waitress and sometimes I need it to keep my blood sugar up so I can make it to my break to eat. I drink 90% water all day I would say sometimes iced tea too. In a given day I would say I drink no more the 6oz of soda on a good day 4oz. What are your thoughts on soda during pregnancy?