Hi OB nurse here. I know at our hospital and any others I have been at you would not be allowed to bring and serve your own. We ask the parents what they would like to use, if you have a specific reason that you feel you need to start on a soy it is availible. Otherwise usually Enfamil and Similac are both availibe. I know someone mentioned that their hospital had Nestle too, but this is not as common, there is some debate out there about that formula among pediatricians. Also check with your pediatrician--some peds have a formula they insist their babies start on and that is what is ordered and what we have to feed them. As far as what hospitals use if the parent does not know or is undecided there are 2 answers to this. Either who the hosp has the best arragment with--most hospitals have gotten away from this as it is really not a good practice sometimes involving kick backs, promos, meals etc....... or currently Enfamil as it has the WIC contract and so it is the default. If you are using WIC you should start the baby on the WIC formula as it is the only formula they will provide until there is clear proof your baby needs something different. If you plan to use a product not provided at the hospital talk to your pediatrician about when is the best time to switch and how they would like you to do that. It usually needs to be a gradual switch. This does not include the difference in feeding ready to feed vs powder of the same formula. Good luck with our new baby.