Dehydration in Newborns and Infants

Signs, Causes, Treatment, and Prevention

Mother holding her hand to the forehead of her crying baby girl

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Newborn dehydration, or dehydration in infants, is not unusual, but can quickly become a serious medical concern if not addressed quickly. Luckily, it can usually be remedied by simply feeding your baby more and more often. However, it's very important to check in with their pediatrician to ensure their hydration levels quickly return to normal.

What Is Dehydration?

Dehydration is the state of not having enough fluid in the body for it to carry out its normal functions. Due to a baby's small size, a lack of fluids can quickly become a serious medical issue.

Water is a key component of every cell. It is vital for temperature control, maintaining organ and tissue health, carrying nutrients to cells, and optimal functioning of every body system.

Each day, your child loses water through urination, bowel movements, sweating, crying, and even breathing. It is replaced each time they eat or drink. Maintaining hydration is one reason why newborns need to feed (either via breastfeeding or bottle feeding) so frequently.

A number of issues can throw off the balance between depletion and replenishment. For example, if your baby vomits or has diarrhea, they will lose fluid more rapidly than when they are well, potentially resulting in dehydration. Additionally, if your baby goes on a nursing strike, is not nursing well, or is having issues with bottle feeding, they might also become dehydrated.

Note that infant hydration isn't just about water. Babies' bodies need both sufficient fluid levels and electrolytes, which are minerals, such as salt, that help regulate fluid balance. There are three main types of dehydration: loss of water, insufficient electrolytes, and low levels of both water and electrolytes.

Signs of Dehydration in Infants

Newborns and older babies can become dehydrated quickly. Be on the lookout for these signs, especially when your baby is sick, overheated, or having trouble feeding (e.g., during a nursing strike or when teething). The most common signs of dehydration in babies include:

  • Concentrated urine that looks very dark yellow or orange
  • Constipation
  • Dry lips
  • Dry mouth
  • Dry mucous membranes
  • Excessive sleepiness
  • Irritability
  • Less than six wet diapers in a 24-hour period
  • No interest in taking a bottle or breastfeeding
  • No tears when crying
  • Paleness
  • Sunken fontanelle (soft spot) on their head
  • Wrinkled skin

Note, however, that babies can become dehydrated even when there aren't obvious signs. So, it's crucial to make sure your infant is getting enough liquids. One way to monitor this is to check if they are regularly producing wet and soiled diapers, which in newborns should occur after most feedings and/or every few hours or more.

Causes

A number of things can cause dehydration in infants. While dehydration can affect anyone, at any age, it is more common in little ones than adults, because newborns' bodies have more water (78%) than adults' do (about 60%). Babies also metabolize at a higher rate, meaning their bodies use water faster.

Newborn and infants dehydration may be caused by:

  • Bottle-feeding issues: Bottle-fed babies may become dehydrated if they're not taking a bottle often enough or they're not taking in enough infant formula or pumped breast milk at each feeding.
  • Breastfeeding issues: Breastfed babies can become dehydrated if they're not latching on correctly, not breastfeeding often enough or long enough, or there's an issue with breast milk supply.
  • Diarrhea: If your child develops diarrhea, fluid is lost with each bowel movement (sometimes significant amounts).
  • Fever: A rise in your child's body temperature can cause a greater loss of fluids. Plus, babies may not take feedings as well when they have a fever.
  • Overexposure to heat: High temperatures, extreme humidity, or spending too much time outdoors in the hot sun can cause sweating and the evaporation of fluids through your baby's skin.
  • Refusing to eat: Babies may refuse the breast or bottle if they are in pain or not feeling well. A stuffy nose, earache, or sore throat can interfere with sucking and swallowing.
  • Vomiting: When babies aren't able to keep down most of their feedings, they're losing important fluids that their body needs. Repeated vomiting can quickly lead to dehydration.

Dehydration in newborns and young infants is usually the result of not taking in enough fluids via feeding to replace what is lost in the course of the day.

Older infants and children are more likely to become dehydrated from an illness than newborns are.

Treatment

The treatment for infant dehydration depends on the cause and severity of the condition and the age of the baby. For newborns or young infants under 3 months old, your doctor will likely want to see the baby for a check-up. If diarrhea or other illness or condition has been prolonged, the doctor will likely want to see your baby regardless of age.

If your child is showing any possible signs of dehydration, call a healthcare provider. They can let you know if your child needs to be seen and/or recommend the appropriate treatment.

Severe dehydration can be a very dangerous and even life-threatening situation. So don't hesitate to seek emergency care if signs are significant, you can't reach your doctor, or you are otherwise concerned.

Get immediate medical attention if your baby:

  • Has a sunken fontanelle
  • Has diarrhea for more than eight hours
  • Has other prolonged or severe signs of dehydration
  • Is not breastfeeding or bottle feeding well
  • Is under 3 months old and has a fever
  • Is vomiting after two feedings in a row
  • Seems to be struggling

At Home

If your child's symptoms are mild, your doctor may tell you to begin treating your child at home while continuing to carefully monitor their symptoms.

You'll likely be advised to follow these steps:

  • Keep track of your baby's feedings and wet diapers.
  • Move your baby to a cool place and remove excessive clothing or blankets if the temperature is very warm and your baby is overheating.
  • Offer a bottle or breastfeed frequently, especially if your baby isn't taking in very much at each feeding.
  • Wait on other drinks. Do not give your baby an oral rehydration fluid (e.g., Pedialyte), water, juice, or soda for illness, vomiting, or diarrhea without talking to your doctor first. Aside from the fact that these drinks may not be age-appropriate, giving them the wrong liquid and/or amounts can worsen dehydration.

If your child's pediatrician recommends oral rehydration fluid, follow their instructions. These fluids are different from other drinks in that they contain electrolytes and are specially designed to rehydrate quickly.

At the Doctor's Office

If your doctor advises you to bring your baby in for a check-up, they will do a thorough evaluation of your baby to determine the best course of treatment.

For breastfeeding parents, the doctor may want to check your baby's latch and breastfeeding technique. If you're breastfeeding and your baby isn't getting enough breast milk, you may be advised to consult with a lactation consultant and/or to supplement your baby with pumped breast milk or infant formula.

The doctor will also examine your child's overall health. If the baby has an infection, the doctor may prescribe medicine to treat the illness.

At the Hospital

If the dehydration becomes severe, your baby may need to go to the hospital. There, caregivers can monitor your baby's intake and output of fluids. They may also give your baby IV fluids to replace what has been lost, especially if the baby is not eating well or has severe vomiting and diarrhea.

They may also prescribe medicine for your child to treat any illness or underlying cause.

Prevention

The best way to prevent dehydration in infants is to not only know the signs and understand the causes but to also know how to keep it from happening in the first place.

Feed Your Newborn Frequently

If you're bottle-feeding, offer one to three ounces of infant formula or pumped breast milk in a bottle every two to three hours. If you're breastfeeding, put your baby to your breast at least every two to three hours around the clock. Wake sleepy newborns up to breastfeed or to take their bottle if it's been more than three hours.

As the weeks go on and your baby begins to take more at each feeding, they may be able to sleep longer between feedings.

Do not stop feeding your child to try to stop diarrhea or vomiting. Your baby needs extra fluids to replace what they're losing. So, continue to breastfeed or bottle-feed as often as possible while your child is ill and recovering.

Monitor Wet Diapers and Weight Gain

Keep track of the number of wet diapers your baby is having each day and see your baby's doctor for regular well-baby checkups to monitor for healthy weight gain.

Stay Out of Extreme Heat

Try not to take your newborn or young infant outdoors if it's very hot or humid. If you need to be outside, keep your baby in the shade and as cool as possible.

Babies can also overheat inside in a hot, stuffy room or car, or if they're all bundled up. Try to keep your baby comfortable. Breastfeed and offer a bottle often to replace the fluids that they're losing if their environment is hot.

Avoid Giving Water

You don't have to give your baby a bottle of water between feedings to try to prevent dehydration. In fact, it's best not to unless otherwise directed by a healthcare provider.

Water fills the baby up and doesn't provide any nutrients. Both breast milk and infant formula provide your baby with fluid and nutrition.

The American Academy of Pediatrics says that babies should only be given water starting at age 6 months. At that point, their daily consumption of water should be limited to 4 to 8 ounces.

Prevent the Spread of Germs

Avoid stomach bugs that can make your baby sick. Wash your hands often, especially before preparing your child's bottle and after changing diapers or using the bathroom. Keep hand sanitizer handy.

Remind family members and friends to wash their hands. Ask them not to visit your child if they are sick—particularly when your child is a newborn and young infant.

A Word From Verywell

Babies lose fluids during the day, but they get all the fluids they need to replace what's lost through their regular feedings. It's a natural balance. When there's a shift, a baby can easily become dehydrated. By understanding this common condition, its causes, and warning signs, you can try to prevent it or at least catch it early.

Always check with a healthcare provider if you see signs of dehydration or are concerned about your baby's eating patterns, weight gain, or hydration level.

9 Sources
Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading
  • American Academy of Pediatrics. New Mother’s Guide to Breastfeeding. Bantam Books.

  • Lawrence RA, Lawrence RM. Breastfeeding: A Guide for the Medical Profession, Eighth Edition. Elsevier Health Sciences.

  • Riordan J, Wambach K. Breastfeeding and Human Lactation, Fourth Edition. Jones and Bartlett Learning.