The Real Reason Babies Can't Drink Water

In general, drinking water is a very good thing. We're always being told to hydrate, hydrate, hydrate, and nagged to get in our eight glasses per day. There is one group of people, however, who shouldn't touch so much as a drop of the stuff — H20 can be harmful, or possibly even fatal, to infants under 6 months old.

Why is water so dangerous for babies? As Business Insider points out, babies' body composition is markedly different from that of adults or even older children. While an adult's body is about 55 to 60 percent water, babies are 75 percent water. Their tiny kidneys can only handle so much water on top of that. 

As Dr. Jennifer Anders, a pediatric emergency physician at Johns Hopkins Children's Center, cautions parents, these immature kidneys can result in babies' bodies releasing sodium along with any excess water they take in. This can lead to a condition called water intoxication which can be life-threatening in infants if not treated right away (via Reuters).

How to keep your baby safe from water intoxication

In addition to never feeding water to babies under 6 months old (and only small sips to babies who've yet to reach their first birthday, according to BabyCenter), it is crucial that you not over-dilute formula. You should also keep baby out of the swimming pool, or at least make sure their head stays above the water, as ducking below the surface could lead to accidentally sucking in water.

Avoid giving electrolyte-replacing pediatric drinks unless they are specifically prescribed by a doctor in case of dehydration. In fact, you should not be giving baby anything to drink other than breast milk or properly-diluted formula.

What to do if your baby does drink water

If you think your baby may have taken in any amount of water, it's important to be aware of any possible signs of water intoxication such as irritability, drowsiness, low body temperature, a swollen or puffy-looking face, and seizures.

Should you see any of these signs, you'll need to take your baby to a hospital right away. It may be necessary for a doctor to administer an intravenous saline solution to bring their sodium levels back to where they should be. As long as your baby gets prompt medical attention, though, there should not be any lasting damage.