So exactly why can’t babies drink water?
Babies get all their nutrition from breastmilk/approved infant formulas, including very important trace elements (vitamins and minerals) that are essential for their rapid growth. If they are offered water, they may feel full and not drink enough milk.
Water in the guts can also prevent the baby absorbing all the good stuff from the milk it has drunk.
These two issues can make them seriously ill and lead to malnutrition and developmental difficulties if they are denied those essential trace elements for long enough.
For the same reason, diluting formula with more water than instructed can make a baby very sick, as the diluted formula won’t contain enough nutrients but will fill the baby up.
If a carer decides to give a breast-fed baby a bottle of water, which can be consumed by the infant with much less effort, it may take in more fluid then it needs which can not only cause malnutrition but water intoxication (see more below).
Also, giving water to babies who breastfeed can reduce the mother’s milk supply.
From what age can babies start drinking water?
When can babies drink water?
You can introduce small amounts of water to infants from the age of six months, usually at the same time as they start solids.
Is tap water bad for babies?
No, it's OK for them to drink in addition to their milk, as long as they are six months or older. Some recommend using boiled water from the tap till they are 1.
Do babies drink water or just milk?
Milk is the most important nutrient for a baby till they are 1. After six months, they can drink some water. But, most importantly, take care that water doesn’t replace any normal milk feeds.
It is a good idea to offer them some sips of water with meals to start with. This may help with constipation which can happen when babies start solids, it gets them used to the flavourless taste of water and sets up good habits for childhood when breast milk/infant formula is no longer their main source of hydration.
When starting you can offer them water with a spoon, as they don’t need much to start with, and progress to a cup as their co-ordination develops.
Mama Natural suggests when starting to use a sippy cup, show the baby first how you drink from it, so they can copy you, and make sure they are sitting up as they may cough or splutter when learning to use it.
Again, drinking water should not be given in large amounts at this age, between 6 months and 1 year old, as their main source of liquid should be breast milk/infant formula. They will also be getting hydration from a secondary source, their early solids, which are usually pureed fruits and vegetables that have high water content.
You don’t want the baby to fill up on water and solids and miss out on the essential goodness of their milk!
By the age of 1 they should be OK to regulate their own water intake.
What if your baby is hot or has a fever?
Can babies drink water in any particular situation?
The World Health Organisation says “Breast milk is more than 80% water, especially the first milk that comes with each feed. Therefore, whenever the mother feels her baby is thirsty she can breastfeed him or her. This will satisfy the bay’s thirst, and continue to protect the baby from infections, and help the baby to continue to grow well.”
As for formula-fed babies, Pregnancy Birth and Baby suggests: “If they are under 6 months and formula-fed, you can offer smaller amounts of formula more frequently. Do not offer water unless advised by a doctor.”
It also recommends if the weather is hot and you are breastfeeding, make sure you drink plenty of water. This will help with your milk supply. (Drinking plenty of water is a good rule generally for the mother while feeding).
You can tell if the baby is hydrated enough if it has 6-8 wet nappies over 24 hours, though this can be tricky to observe with disposable nappies. They should be heavier if wet.
If the GP or paediatrician is concerned about dehydration, they may suggest a solution such as Hydralyte, but never give a product like this to a baby without checking with a medical professional first.
What to do if your baby has drunk water
It depends how much water they have been given and over what length of time. It can't hurt to check in with your GP, paediatrician or ring Health Direct on 1800 022 222.
Although it is rare, the most urgent concern is water intoxication: do look out for signs of puffiness in the face, temperatures at 36.1 degrees or less and, most seriously, seizures. If you notice any of these symptoms, seek urgent medical help.
“Water intoxication happens when too much water dilutes the concentration of sodium in the body, upsetting the electrolyte balance and causing tissues to swell.” Stephen R Daniels tells BabyCenter.
Water intoxication can happen not only from giving a baby straight water, but also from diluting formula.
A US couple were charged with the death of their 10-week-old daughter after watering down feeds because the mother did not produce enough breastmilk and couldn’t afford formula, Essential Baby tells. “Baby Nevaeh suffered hyponatraemia (water intoxication) as a result of drinking the watered-down milk. The condition saw her electrolyte and sodium levels drop and made her brain swell.”
And the article goes on to report of an Australian six-month old being hospitalised with seizures after her mother gave her cordial, also because she couldn't afford formula.
Paediatric doctor Jennifer Anders tells Reuters Health that the problem is that babies don’t necessarily know when to stop, especially when drinking water instead of the more filling option of milk.
“Even when they’re very tiny, they have an intact thirst reflex or a drive to drink,” she says. But babies’ kidneys are not developed enough to handle too much water.
“When they have that thirst and they want to drink, the fluid they need to drink more of is their breast milk or formula.”