If you are the parent or caregiver of a baby, you may be concerned about dehydration — especially if the baby is having trouble feeding or hasn’t been feeling well.
Dehydration in children is common, but it tends to occur even more frequently in babies than in older kids. “Dehydration is more common in babies due to their small size and how quickly their bodies utilize the fluids they take in,” explains Laura Varghese, a nurse and lactation consultant at Elliston Pediatrics.
Dehydration can occur when babies don’t take in enough fluids, or when babies lose too many fluids, such as when they are sick. Either way, it’s important for caregivers to understand the signs of dehydration in babies, how to prevent it and when to seek help.
Here, we’ll go over everything parents and caregivers need to know about dehydration in babies.
Why is dehydration more common in babies?
Overall, babies require more fluids than older children and are more sensitive to fluid losses, says Dr. Jenelle Ferry, board-certified neonatologist and director of feeding, nutrition and infant development at Pediatrix Medical Group.
“Because infant’s bodies are overall smaller, it takes a smaller total loss of water to become dehydrated,” Dr. Ferry explains. “Infants also have a much larger surface area (skin area related to their overall mass) and can therefore lose more water daily,” she adds.
Why is dehydration more dangerous for babies?
Being properly hydrated is vital for the health and well being of infants, Ferry emphasizes. “Water is critical for cellular functions, transport of nutrients, regulation of body temperature, protection of vital organs and more.”
While adult bodies are about 60% water, babies’ bodies require more water. Babies’ bodies are 75-85% water, and this number is even higher in premature infants, says Ferry. This level doesn’t start to decline to adult levels until babies are between 1-3 years old.
Anytime a baby isn’t getting enough fluids or loses fluids from vomiting or diarrhea, they risk becoming dehydrated, says Varghese. “When this happens, their electrolytes become imbalanced,” she explains. “If left untreated, this imbalance can cause seizures, brain damage and even death.”
“The earliest signs of dehydration will be fewer wet diapers or the urine in diapers appearing darker yellow.”
—Dr. Jenelle Ferry, neonatologist and director of feeding, nutrition and infant development, Pediatrix Medical Group
Signs of dehydration in babies
It can be frustrating when you have a baby who you suspect may be dehydrated, because they can’t tell you how they are feeling. That’s why understanding signs and symptoms of dehydration in babies is essential.
According to Busenlener, some common signs of dehydration in babies include:
- Increased thirst.
- Decreased urine output.
- Dry mouth.
- Cracked lips.
- No tears when crying.
- Sleepiness and lethargy.
- Light-headedness.
- A sunken fontanel (soft spot).
It can also be helpful to break down the signs of dehydration to two phases — early signs and late signs.
Early signs of dehydration in babies
“The earliest signs of dehydration will be fewer wet diapers or the urine in diapers appearing darker yellow,” says Ferry. Another relatively early sign is if you see fewer tears than normal or no tears. Extreme drowsiness is another possible early sign, Ferry says.
Later signs of dehydration in babies
As dehydration progresses, you may see other signs, according to Ferry. These include:
- Cold and blotchy hands and feet.
- Rapid breathing.
- Dry mouth.
- Eyes appearing darker or sunken.
- Sunken soft spot (anterior fontanelle) on the head.
What causes dehydration?
Dehydration in babies can have numerous causes, says Dr. Tanya Busenlener, pediatrician at Children’s Hospital New Orleans. The most common are:
- Losing fluids from illness (vomiting, diarrhea, fevers).
- Breastfeeding problems
- Inadequate formula intake.
Feeding issues are most common in younger babies, and there are a few reasons for this.
Babies are more susceptible to illness
First, babies are also more likely to pick up viruses than their younger counterparts due to their less mature immune system, Busenlener says. Viruses that cause vomiting and diarrhea can quickly make a small baby dehydrated, especially if they aren’t able to have their fluids replaced fast enough or if they are lethargic from illness and are finding it difficult to feed.
Babies can’t easily communicate symptoms
On top of all this, babies and young children can’t express when they are experiencing symptoms of dehydration due to feeding issues. “Babies and young children are dependent on adults to give them fluids and might not be able to tell someone that they are thirsty,” Busenlener describes.
Feeding issues are most common in babies 6 months and under
Whether breastfeeding or formula feeding, issues with feeding are a top cause of dehydration in babies aged 6 months and younger.
In breastfed babies, Varghese says insufficient milk supply, poor latch or milk transfer issues may contribute to dehydration.
Meanwhile, formula-fed babies may become dehydrated if they aren’t receiving enough ounces per feeding or are feeding infrequently. Formula shortages and economic factors can also impact the amount of formula available to a baby.
Dehydration in newborns
It’s important to note that it’s normal for babies to lose a little weight and experience slight dehydration in the first few days after birth. “When a baby is first born, they lose water weight … and the number of wet diapers is very small (one in the first day, two in the second, three in the third),” Ferry says.
At the same time, dehydration in newborns can occur if they aren’t receiving enough milk or formula in the early days. “In this age group, the most common cause of dehydration is decreased [food] intake,” Ferry says. “This can occur for many reasons, but especially if an infant is having trouble with breastfeeding in the first few days or if Mom is having trouble establishing a milk supply in the first one to two weeks of life.”
How to prevent dehydration
Preventing dehydration is key. If a baby doesn’t become dehydrated in the first place, you don’t need to worry about how to treat the dehydration — or other health impacts.
Preventing feeding-related dehydration
Preventing dehydration during breastfeeding or formula-feeding means understanding clearly how much fluid intake is right for your baby and how to ensure adequate intake.
Varghese says formula fed babies should have anywhere from 24-32 ounces of formula per day. For breastfed babies, she advises the following:
- Ensure the baby is latching well.
- Fed every two to three hours.
- Looks for signs of good milk transfer (audible swallowing, adequate diapers, baby is content).
If there are breast milk supply concerns, it’s important to seek help from a lactation consult or the baby’s doctor. They may suggest supplementation with pumped breast milk or formula.
“It is critical that all parents know that babies under 6 months old should never be given plain water to preserve hydration.”
—Dr. Jenelle Ferry
Preventing dehydration during illness
It’s important to take a preventative approach when a baby isn’t feeling well, such as when they are vomiting, having diarrhea or experiencing fever. Chat with the pediatrician about starting an oral hydration solution, such as Pedialyte, as soon as vomiting or diarrhea begins, Busenlener recommends. “Give extra fluids when it is hot outside or they are sweating a lot.”
If you are breastfeeding, it’s OK to continue feeding breast milk during times of dehydration, provided they are able to keep it down, adds Busenlener.
Whatever the case, do not give infants plain water to rehydrate. “It is critical that all parents know that babies under 6 months old should never be given plain water to preserve hydration,” Ferry emphasizes.
“Giving water can decrease necessary calorie intake, as little tummies fill up fast, and more importantly it may cause life-threatening consequences,” Ferry explains. “Baby kidneys are not quite able to do the job of filtering extra water, which can lead to dilution of sodium in the body and swelling in the brain, leading to seizures or even coma or death.”
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When to seek help
According to Busenlener, caregivers and parents should seek medical care if a child exhibits any of the following symptoms:
- Diarrhea for more than a few days.
- Vomiting for more than a day.
- Inability to keep fluids down.
- Unwillingness to drink or nurse for several hours.
- No urine output for more than 4-6 hours in infants.
As babies get more dehydrated, you may notice they have decreased activity. It’s best to contact your pediatrician immediately. “If they are not waking to nurse or bottle feed, this can be leading to an emergency,” Ferry warns.
The bottom line
Dehydration in babies is something that all caregivers need to be aware of, and taking steps to prevent dehydration is vital. Understanding the signs of dehydration — such as fewer wet diapers, dry mouth, decreased tears, and lethargy — is important for babies in distress, especially since infants can’t tell us when something is wrong.
If you have questions about feeding and hydration, or feel unsure about whether you are dealing with dehydration or something else, you shouldn’t hesitate to reach out to the baby’s pediatrician. It’s always best to err on the side of caution when it comes to a baby’s health, the experts agree.
