is all soy formulas the same?

the hospital put her on similac soy..then WIC gave me enfamil soy..she poops almost everytime she eats..she is gaining weight and the doctor said if shes not fussing and spitting up to keep her on it...i was just asking if the two brands are the same ingredients just diff name?? the doctor said they were..idk..any thoughts on this??

I've always read and been told that all formula was FDA regulated and was required to maintain the same amount of ingredients.