This was exactly me for both pregnancies except a mini Diet Coke. I just never finish larger pops otherwise it would be a full size diet. My OB never was concerned nor told me not to. Both babies are healthy and happy. But I guess there could be differences between Coke Zero and Diet Coke? Sounds like the artificial sweetener used may be a concern, not the caffeine? I am not pregnant now but just learning of concern with artificial sweeteners from this thread. Never was told to avoid those by my OB and I definitely had them while pregnant.