Quite frankly, having been generally virtuous about your health - staying off too much caffeine, alcohol and possibly having given up cigarettes - you really don't need to crucify yourself by giving up cream cakes and chocolate, too. However, one of the easy traps to fall into is substituting espressos and wine with soft drinks.
True, fizzy drinks can help stave off feelings of pregnancy queasiness, and there is a limit to the amount of water or fruit juice you'll fancy drinking when your friends are on the hard stuff, but watch out for a few things...

Too much of a bad thing
Forget computer games and biscuits, fizzy drinks are one of the major causes of childhood obesity in the UK. Just because you're a grown up, the goal posts haven't moved. True, pregnancy is not a good time to diet, but it's also not a great time to feast on empty calories, so keep an eye on how much you are drinking. Buy fizzy drinks in small bottles or cans so that you don't feel the urge quite so easily to take a top up from that mega two-litre bottle in the fridge door.

When 'diet' is a four-letter word
OK, so this may sound contradictory to the suggestion above, but going for the full-on sugary version of a soft drink is preferable to the ones containing sugar substitutes. Although there is not a great deal of research in this field involving pregnant humans, it is generally considered that aspartame rather than saccharin is a preferable sweetener. In animal tests, higher incidences of cancer were found in the babies of mothers who had saccharin in their diet.

Be natural
Where possible, try to stick to buying drinks from the growing number of companies who are making soft drinks with fewer additives and in some cases even organic ingredients. Any supermarket will now have a good few options, though you might find these in their 'health' aisle rather than next to the regular soft drinks.