I wasn't a big soda/coffee drinker before getting pregnant. Before baby, I used to drink it occasionally and I do the same now. I try to only have a small cup of coffee on the weekends & none during the week. Soda is always a special treat (going out for dinner or a fountain drink from Costco), so I have it rarely.
I thought maybe it had an adverse affect on LO, but he was so little (like 4 weeks) that I think it was more from being an unpredictable newborn. Now when I have some (8 weeks) he doesn't show any changes.