It is ideal to give your pregnant pit bull a puppy diet or nursing diet. These diets are full of nutrients. Dogs during pregnancy not only need diets of high quality but their dietary requirements are also increased. This is due to the fact that she needs food not only for herself but also for growing puppies. Their dietary requirements are increased up to 30% during pregnancy. So, you should give her 4-5 servings in a day and also increase the amount of food per serving.