Dehydration in Babies, Newborn & Infants

In the early months of their lives, newborns and babies stick to a purely liquid diet, either in the form of a bottle or breastfeeding. Given the amount and frequency they consume, it can be difficult to imagine they are ever dehydrated, but it can be  very common.


Dehydration in newborns and babies will typically mean they have lost too much water, and simply cannot ingest enough milk and fluids to instantly replace it. As they start to grow and develop into toddlers – learning to charge around with new forms of play and adventure – water loss can be accelerated as they breathe, sweat, cry and go to the toilet,.  This can have a range of impacts on their wellbeing and development.


In this article, the zazen Team explore signs of dehydration in babies, infants and toddlers, as well as the common causes, symptoms, and remedies on how to treat dehydration.


Signs of Dehydration in Babies & Toddlers

Every child is different, so the signs and symptoms of dehydration in babies and infants will depend on the extent of water loss, their level of individual development, and other environmental influences. There are, however, a number of common signs that can indicate dehydration, such as with newborns:

  • More concentrated urine with a darker yellow colour
  • Sunken eyes
  • Sunken fontanelle (this is the soft spot in the centre of the top of their head
  • Crying without tears
  • Less than six wet nappies in a 24-hour period, or at least nappies that remain dry for between 2 – 3 hours, suggesting a reduction in urinary output
  • Dry mucus membranes, such as cracked lips
  • Dry skin


As your newborns grow into babies and toddlers, their activities will change and so will their eating and drinking habits. Even if they might have started saying their first words, they won’t be able to recognise and communicate they are dehydrated, so it is important to look out for these signs of dehydration in babies, infants and toddlers:

  • Overly tired or cranky behaviour
  • Sunken eyes
  • Dry mouth and cracked lips
  • Cold hands
  • Accelerated breathing & fast heart rate whilst they are at rest
  • No interest in playing
  • Dry nappies for longer than six hours


Dehydration can develop and become serious very quickly.   Hopefully parents recognise these early signs of dehydration but in some cases where the condition develops into an extreme situation, children can  become either delirious in their actions, or fall completely unconscious.  In this case seeking immediate and urgent medical attention.


Causes of Dehydration in Babies


There is a myriad of causes for dehydration in newborns, babies and toddlers, so it is important to be vigilant and aware of the warning signs or when they are most at risk.


In Newborns

Newborns are still becoming accustomed to the new world around them, and that includes feeding. It is incredibly common to notice a few hiccups when first learning how to drink milk, as well as some difficulties swallowing and digesting it. Furthermore, it is possible your newborn will also struggle latching on to receive the milk, leaving them to lose a bit of weight during their early weeks.


Common causes for dehydration in newborns are:

  • Failure to properly latch on to the nipple and feed
  • Initially low supplies of breast milk
  • Too much vomit or spit up
  • The breast milk does not hold the desired balance of salts and water


In Infants & Toddlers


As your child grows and develops, the causes of dehydration will be very similar to our own as adults. Basically, it can stem from any event where the amount of water entering the body is excessively outweighed by the amount going out. As babies and toddlers have smaller bodies,  they are more susceptible to dehydration. It is important to look out for:

  • Diarrhea
  • Fever
  • Vomiting
  • Unsatisfactory intake of fluids during a period of illness
  • Excessive sweating
  • Prolonged exposure to hot and humid environments
  • Relations to chronic conditions, such as diabetes and bowel disorders


How common is dehydration in newborns and babies?


Dehydration is more common in newborns who are struggling to latch, and it continues as the child develops, as they cannot communicate when they are feeling either thirsty, or the early symptoms of dehydration.


Remedies and Treating Dehydration in Babies & Infants



Newborns that are having difficulty with latching on need to be breastfed at consistent and frequent stages throughout the day to ensure they are receiving enough fluids. You can give them the opportunity to latch on until they fatigue and break away themselves. Intervals can be as regular as every 15 – 30 minutes until they become used to it.


Bottle or dropper feeding

Should breastfeeding continue to prove unsuccessful, or there is not enough milk production, then it is important to try alternative methods of delivering milk, such as pumping breast milk or using  baby formula. You can also use a bottle or a sterile dropper to carefully and slowly feed your baby milk until they become more confident and capable consuming and digesting the milk.


Dress them in light clothing to combat night sweats

Is your baby or toddler sweating whilst they sleep at night? Be sure to dress them in clothes that are light and highly breathable. Apply the same logic to their bedding, and even consider adjusting the air conditioner to avoid them overheating.


Give them a bath during a fever

Fevers are always difficult times for new parents. Should your baby or toddler develop a fever, then it can prove helpful to lower their body temperature by giving them a gentle sponge bath with lukewarm water.


Juicy fruits

Try getting them to eat their way to hydration. Young children may not like drinking water or milk, but they always love munching on juicy fruit and vegetables high in water content, such as plums, cucumbers, and watermelons.


When to see a doctor if your infant is dehydrated?

Best practice (especially when you are a new parent) is to contact your chosen health care professional when your babies or toddlers are experiencing the signs of dehydration listed above, as you will be able to consult with them on your unique situation and receive tailored advice.


There may be times, however, where symptoms persist and worsen, and more immediate treatment is required. These cases can include blood appearing in vomit, and continuous bouts of serve vomiting and/or diarrhea that last more than a few days. Hospitalisation may be required, with the administering of IV fluids and monitoring of electrolyte balances taking place.


How much water should a baby drink?


Babies are not recommended water until 6 months of age for numerous reasons, and even after that, a gradual start is preferred.


For ages 6 to 12 months, parents are advised to balance the solids they give their children with the amount of milk consumed. During this period, babies generally do not need more than 60 to 120 millilitres of water per day.


Once they hit 12 months, they can progress to drinking approximately 240 millilitres a day, with the amount increasing each year (i.e. two years will be 480 millilitres, three years 720 millilitres and so on). Remembering each child is unique and needs to be supported at their own pace.


Stephens C, Iftikhar N, How to Recognise and Treat Dehydration in Babies and Toddlers, Healthline, 2020

Marusinec L, Cafasso J, The Warning Signs of Dehydration in Toddlers, Healthline, 2016,

Resnick M, Novak S, Dehydration in Babies, What to Expect, 2021

Resmovits M, What Does It Mean if My Baby Has a Sunken Fontanelle?, What to Expect, 2020,

Crider C, Nwadike V, Is Breastfeeding Supposed to Be This Painful? Plus Other Nursing Issues, Healthline, 2019,

Vega RM, Avva U. Pediatric Dehydration. [Updated 2021 Aug 9]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from:

Cleveland Clinic, Dehydration and Your Child, 2020,

Anzilotti A, Dehydration, Kids Health, 2020

Mirchandani A, Gill K, When Should My Baby Drink Water? Healthline, 2018

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