You don’t need to give your baby or newborn water until she’s about four months old or when she starts solid foods. That’s because newborns get plenty of hydration from drinking breast milk and formula. And giving a young baby water can actually be harmful: A newborn’s kidneys might not be able to concentrate or process the water properly because of too much salt in the water. Water intoxication could occur if baby consumes too much water and loses too much sodium. If her sodium levels decrease in her bloodstream, that can cause brain swelling or seizures. That’s why, if you’re feeding baby formula, it’s important to make sure you follow the mixing directions carefully and don’t add extra water.
There are certain occasions where babies might need a small amount of water in very hot weather, but you’ll want to talk to baby’s pediatrician first. Once it’s time for baby to have water, if she consumes the appropriate amount of formula (up to 32 ounces a day) or breast milk (8 to 12 feedings a day), you can offer four to six ounces of water a day. Cold water can be a fun way to introduce a sippy cup when baby’s around six months old, and it can be soothing on teething gums.
If you’re worried that baby’s dehydrated, you can look for warning signs like she isn’t urinating the normal four to six times a day and she doesn’t have clear or pale-yellow urine. Those things would indicate that baby might be dehydrated, and you’ll need to talk to her pediatrician about the problem.
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