Have you ever heard this bad breastfeeding advice: “Would you want to drink warm milk in the summer? No! Don’t nurse your baby when it’s hot out, get them a glass of water!”? Just because it’s warming up does not mean that you need to change your nursing habits!
Exclusively breastfed babies do not require additional water as long as baby is allowed to nurse on cue. Even in very hot summer conditions, your baby can get all their needed hydration from your milk. For older babies, too much water can interfere with breastfeeding because it fills baby up so that he nurses less. Babies need the nutrition and calories in breastmilk to grow – water has none of these. But it does have hydrating fluids and electrolytes so, fear not! As long as your baby is nursing on demand they will not become dehydrated!
“Your baby can design his own meal to suit his needs. If he’s thirsty, he nurses for a shorter amount of time and gets a lower fat milk. Still thirsty? He asks to switch sides sooner and gets another thirst-quencher from the other side. Extra hungry? He stays longer on the first side or nurses more vigorously, to pull down more higher-calorie fat globules.” – The Womanly Art of Breastfeeding, “Nesting” So your job really is only to stay responsive to what your baby is telling you.
More info and citations at: kellymom.com/nutrition/starting-solids/baby-water