Dehydration in babies

How can I tell if my baby is dehydrated?

If your baby is dehydrated, it means she's losing too much fluid or not taking enough in.

Any of these signs may mean your baby is dehydrated:

• dry lips, mouth and eyes, with tearless crying
• a sunken fontanelle (the soft spot on the top of your baby’s head)
• fewer wet nappies than usual
• dark yellow wee
• lethargy and drowsiness
• rapid breathing
• cold and blotchy-looking hands and feet
  (NHS 2017)

It’s quite common for babies to get dehydrated. They’re sensitive to fluid loss because they’re small. Babies need more water for their size compared with adults (Koyfman 2018, RCHM 2018a).

It can be hard to tell whether a young child is dehydrated, but if you think your baby may be, take her to the doctor the same day (NHS 2017). Dehydration can become a serious problem if it's not sorted out quickly (RCHM 2018a).

What could make my baby dehydrated?

There are several reasons why your baby may be dehydrated:

Diarrhoea and vomiting
This is the most common cause of dehydration in babies (Koyfman 2018). If your baby has a stomach bug (gastroenteritis), she can lose fluids from diarrhoea and vomiting (NCCWCH 2009, NHS 2017, Tidy 2014).

Your baby may not be able to absorb fluids from her bowels as well as usual if she has diarrhoea. And being sick means she can’t keep fluids in her tummy.

Fever
Fever is another common cause of dehydration in babies. When your baby has a fever, she sweats and water evaporates from her skin as her body tries to cool down (Koyfman 2018, NHS 2017, Tidy 2014).

Overheating
Your baby can easily sweat and lose fluids from being in the sun or being active on a hot day (NHS 2017). She can also overheat and sweat from sitting in a stuffy, hot room, or because she’s wrapped up in too many layers.

Refusing to drink or breastfeed
Your baby may be refusing to drink because:

• She has hand, foot, and mouth disease
• She has thrush in her mouth. Be sure to get treatment for thrush on your nipples if this is the cause of her discomfort, as you can pass thrush back and forth through breastfeeding.
• She has a sore throat.
• She’s teething.
• She has a stuffy nose or cold, making it uncomfortable for her to drink.
  (Burbidge 2017, Tidy 2014)

How can I treat my baby's dehydration?

Your baby’s dehydration isn’t likely to be serious, and you can treat her at home on the advice of your doctor. Your doctor may suggest these treatments:

Offer your baby plenty of liquids
Offer your baby extra breastfeeds as well as sips of oral hydration solution (ORS) as often as your doctor recommends (RCHM 2018a). ORS will help replace the fluids, salts and sugars your baby has lost (NHS 2017, RCHM 2018a). You can buy it at pharmacies.

If you’re formula feeding, your doctor may recommend replacing your baby’s bottle feeds with ORS or cooled, boiled water for the first 12 hours (RCHM 2018a). You can then resume normal formula feeds, but give your baby smaller amounts of formula milk more often, as well as sips of ORS or water. Don’t dilute her formula to encourage her to take in more water (NHS 2017).

Babies on solids can have extra water, too (NHS 2017).

Don’t give your baby fruit juices or carbonated drinks, particularly if she’s dehydrated because of diarrhoea and vomiting (NCCWCH 2009, NHS 2017). Babies shouldn’t have fizzy drinks anyway, but both these and juices can make diarrhoea worse (NCCWCH 2009, NHS 2017).

Give pain relievers
If your baby isn’t drinking because swallowing hurts her throat, you can give her infant paracetamol or ibuprofen to ease her discomfort.

Your baby can have infant paracetamol from when she’s one month old, and ibuprofen from when she’s three months old (RCHM 2018b). Ask your doctor or pharmacist for advice if you’re unsure how much to give your baby. Be aware that ibuprofen can occasionally cause vomiting and diarrhoea, which make dehydration worse (NLM 2016). So stop using it if your baby seems to be getting more sick (RCHM 2018c).

Keep your baby cool
During hot weather, keep your baby in a cool place, out of the sun. Offer her plenty of drinks.

If your baby is only breastfed, she won’t need extra water on a hot day, but she may want to feed more than normal (RCHM 2018a). If your baby is formula-fed or has started solids, offer her cooled, boiled water, too (NHS 2018).

When is dehydration a worry?

Severe dehydration is often a side-effect of other illnesses that make your baby sick or feverish, such as:

• gastroenteritis
• pneumonia
• bronchiolitis

If your baby becomes very dehydrated, she may need to go to hospital for treatment. A doctor will give her rehydration fluid through a soft tube inserted via her nose to get fluid straight into her tummy, or she may need a drip in her arm (RCHM 2018a).

But rest assured that most cases of dehydration aren’t serious, and can usually be treated at home on the advice of your doctor.

Find out more about vomiting in babies – what’s normal and what’s not and discover how to keep your baby safe and cool in the sun.