Why Giving Water to Babies Under Six Months Could be Dangerous

It’s stinking hot. You are sweaty so is your baby. He keeps grizzling and signalling that he wants more ‘boobie’ .  He’s obviously thirsty so you wonder, should I give him a drink of water?

Not only do you not need to offer your baby water in hot weather but it can be unsafe:

Giving water to newborns can affect your milk supply and your baby’s weight gains and for all babies under six months, giving water can dilute the sodium in the baby’s bloodstream to the point where a potentially life threatening condition known as  “oral water intoxication” develops, and this can lead to symptoms like low body temperature, bloating, and seizures.

If you have a newborn, giving water  not only fills your baby’s tummy, which means he will drink less milk and this can affect his weight gains or he may even lose weight, it can also have a negative impact on establishing your milk supply.

In the early weeks after giving birth, you need to feed your baby often to calibrate your milk making potential – if you can get your supply up now, while your post birth hormones are influencing milk production (along with emptying your breasts), you will have a better long term supply and an easier time when these hormones are no longer supporting your milk production to the same extent.

According to physicians at Johns Hopkins Children’s Center in Baltimore babies younger than six months old should never be given water to drink. “Even when they’re very tiny, babies have an intact thirst reflex or a drive to drink,” Dr. Jennifer Anders, a pediatric emergency physician at the center, told Reuters Health. “When they have that thirst and they want to drink, the fluid they need to drink more of is their breast milk or formula.”

Because babies’ kidneys aren’t yet mature, giving them too much water causes their bodies to release sodium along with excess water, Anders said. Losing sodium can affect brain activity, so early symptoms of water intoxication can include irritability, drowsiness and other mental changes. Other symptoms include low body temperature (generally 97 degrees or less), puffiness or swelling in the face, and seizures.

“It’s a sneaky kind of a condition,” Anders said. Early symptoms are subtle, so seizures may be the first symptom a parent notices. But if a child gets prompt medical attention, the seizures will probably not have lasting consequences, she added.

Beyond the newborn stage, your baby still needs the calories and nutrition in milk  for his growth and development. Water has none of these and again, will fill his tummy, possibly reducing his food intake and may affect your milk supply. Or, your baby has been drinking lots of water during the day, he may wake more at night to catch up on milk feeds because he is hungry.

So, what can you do to keep your baby hydrated in hot weather? 

Water as a beverage should be completely off limits to babies six months old and younger, Anders and her colleagues say. Parents should also avoid using over-diluted formula, teas or pediatric drinks containing electrolytes.

Most importantly, respond to your baby’s feeding cues  (smacking or licking his lips, opening and closing his mouth, sucking on his lips, tongue, hands or fingers and ‘rooting’ at your chest) and allow him to breastfeed as much as he needs to quench his thirst.

Breastmilk is composed of 90% water, and that provides all that your breastfed baby needs, even in hot weather. If your baby is thirsty, he will regulate the amount and consistency of your breastmilk by feeding more often and taking in enough of the watery foremilk to satisfy his thirst, but not so much of the creamier hind milk if he is  thirsty but not hungry – you can’t ‘over feed’ your breastfed baby. This means that your baby may seem to ‘snack’ as he feeds frequently but for just a short time on hot days.

When your baby is around six months and  ready to try other foods, he may enjoy a few sips of water from a sippy cup and as he eats more family foods, a little water may help if he seems constipated. If your older baby doesn’t want to try water yet though, don’t worry, an extra breastfeed or several will give him all the water he needs – you can also offer breast milk icypoles if he seems too hot to snuggle close and breastfeed.

Meanwhile, make sure you maintain your milk supply by drinking plenty of fluids yourself – respect your own hunger and thirst signals and consider that tiredness can be an early sign of dehydration.  So, watch your baby, not the clock, and make sure YOU drink water so your baby gets plenty to drink on these hot days.

Pinky McKay is Australia’s most recognised and respected breastfeeding and gentle parenting advocate. She’s a mum of five, with 20 years experience as an Internationally Certified Lactation consultant (IBCLC) and best-selling author of ‘Sleeping Like a Baby’, ‘Parenting By Heart’ and ‘100 Ways to Calm the Crying’ (Penguin Random House).