During pregnancy, it's generally considered OK to drink a soda once in a while. However, you'll want to make sure you don't drink sodas too often because they contain caffeine, sugars, or artificial sweeteners.
A little ice cream won't hurt you or baby — just don't overdo it. As with most things in nutrition, moderation is key. Try to consume a pregnancy diet rich in nutrient-dense foods including healthy fats, filling proteins, and fiber-packed produce.