If it seems like all your baby does is sleep, eat and deliver dirty diapers, things are exactly as they should be. Babies’ tummies are tiny and, compared with bigger kids and adults, reserve less fluid in their bodies.
Add that to their super-busy metabolism and you can see why they need to eat (or, more accurately, drink) around the clock.
While babies can get all the fluids they need from their regular feedings, if your baby is exposed to extreme temperatures or loses fluids due to vomiting, diarrhea or sweating, she can quickly become dehydrated.
Here are the signs of dehydration in babies, along with how to prevent and treat it.
What are the signs of dehydration in babies?
If your baby is vomiting (not just spitting up small amounts of milk), has diarrhea or has otherwise been ill, or if you've been outside in hot weather for a prolonged amount of time, you should watch carefully for signs of dehydration.
Call the doctor if you notice any of the following signs of dehydration in your baby:[1]
- Fewer than six wet diapers in 24 hours or diapers that stay dry for two or three hours, which might be a sign that urinary output is unusually scant
- Urine that appears darker yellow and more concentrated
- Dry mucus membranes (you might notice cracked lips)
- Tearless crying
- Skin seems dry and slack (doesn’t bounce back when gently pressed)
- Sunken eyes
- Listlessness
- Sunken fontanelle — the “soft spot” on the top of her head is sunken or very depressed
In extreme cases, babies need treatment right away and may require rehydration with intravenous (IV) fluids. Go to your child’s doctor or the emergency room immediately if you notice your baby:
- Has not made a wet diaper for six or more hours
- Is extremely fussy
- Is unusually sleepy
- Has cold and/or splotchy-looking hands and feet
- Has very dry mucus membranes (dry mouth, cracked lips, dry eyes)
How much fluid do babies need?
Until she's about 4 to 6 months old, or when she begins eating solid foods, your baby gets all the liquids and nutrients she needs just from breast milk or formula.
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That means there’s usually no need to give her water to keep her hydrated, unless she's lost a lot of fluids in the extreme heat or from vomiting or diarrhea.
Once your baby has started solids, small amounts of fluids will start to come from other sources, such as fruits and vegetables, as well as sips of water.
As the quantity of formula or breast milk your baby takes begins to decrease, it’s important to be sure that her total fluid intake doesn’t, which is why a little extra water, both on its own and in fruits and vegetables, is so important.
And in hot weather, your little one's fluid intake has to increase, so offer more milk and water when temperatures soar — which means it’s especially important to take plenty of fluids with you on any family outings.
Treatments for dehydration in babies
Even if your breastfed or formula-fed baby is throwing up or has diarrhea, continue to offer breast milk and/or formula regularly — at least as often as usual, if not more if she can take it.
Wait an hour after your baby throws up and then offer a teaspoon of liquid every 10 minutes for an hour. If your baby can keep it down, you can gradually increase the amount you're offering.
For older babies who have started solids, water may be sufficient in mild cases.
If there’s substantial fluid loss, especially if baby has a combination of diarrhea and vomiting, your child’s pediatrician may also recommend offering older babies liquids for electrolyte replacement (i.e. drinks such as Pedialyte) to replace sodium and potassium lost in diarrhea and/or small amounts of water.[2]
Make sure you follow your doctor’s advice about how and when to administer these treatments to your dehydrated baby.
How to prevent dehydration in babies when it’s hot outside
When it’s hot outside, the most important step to preventing dehydration in your baby is by protecting her from extreme weather in the first place — which means ensuring she stays out of the sun (a good practice anyway to safeguard that delicate skin) and dressing her in light, breathable clothing.
Never bundle her up in blankets while she’s sleeping (important, since overheating at nighttime has been linked to SIDS).
Dressing Your Newborn for the Heat
How to prevent dehydration in babies due to illness
The most likely scenario for dehydration in babies is when they’re sick. Your baby can lose lots of fluids quickly if she’s vomiting, has diarrhea or refuses to eat due to a sore throat or mouth.
Usually these symptoms are caused by a virus — and although you can’t completely prevent your baby from getting the occasional cold or flu, good hand-washing definitely helps (remind your caregiver, too).
So does staying up-to-date with your child’s well-baby visits and immunizations, since there is a vaccine for rotavirus — one of the most common causes of severe diarrhea in infants and toddlers — that your baby can get starting at 2 months old and of course the flu vaccine starting at 6 months old.
If your baby is showing signs of dehydration, no matter what the cause, always call your pediatrician so that you can get her the treatment she needs as soon as possible. Once she's in a doctor's care, she'll be on the mend in no time.
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