There is research that suggests a high-sugar diet during pregnancy can make the baby more likely to get diabetes. If you are drinking sugared drinks (high fructose corn syrup) please limit yourself to one can a day, even that amount has the equivalent of 12 teaspoons of sugar in it. If you are drinking diet soda, big problems -- the chemicals they use in them are (by some accounts) even worse for you than sugar.
If you want to wean yourself off soda pop, try this -- get some sparkling water (not soda water, which is full of sodium, but sold as seltzer water or sparkling water) and mix it half and half with the soda pop you're hooked on. Soon you'll find that the regular kind tastes like syrup and the half-cut kind tastes just fine. Then try cutting back even farther than that.
My first trimester I was addicted to Dr. pepper. I'm at the end of my pregnancy now and baby is as healthy as can be! So just watch how much you drink!
It's safe in moderation 1-2 cans a day is ok. There's to much caffeine and bad calories in sodas. You need to drink lots of water.