Nothing,its just a soda..
Just don't drink to much. 1-2 cans a day but make sure you drink a lot of water. I have a diet dr pepper thing I can't kick and I wasn't drinking but 4 cups of water and my fluids aren't where they should be. So just drink a lot of water even if it dosnt taste good. I perfer the figi water while pregnant idky but it tastes a lot better
If your worried about it dont drink it,diet cokes really not good even not being preggers
You're better off drinking a regular soda than diet because of the aspartame. Aspartame isn't good for you at all!
They have it caffeine free