I iv been pumping my breast milk an feeding the baby that way... But it comes to thawing the milk I…

I iv been pumping my breast milk an feeding the baby that way... But it comes to thawing the milk I keep in the fridge I'm bottles kinda worrys me cuz the whole water intoxication thing an how baby's can't have water .. An I no he's not drinking the water but just worrys me if any gets in his bottles..