Avoid consuming caffeinated products. If you consume caffeine during pregnancy, it can have a detrimental effect on your developing baby. Your goal should be to avoid all caffeine, but the occasional chocolate or soda is expected and isn't going to deal a devastating blow.
Make sure to watch your diet for foods that can harm your baby when you're pregnant. You must avoid unpasteurized milk, any type of raw seafood, and all soft cheeses.