Dehydration in Babies & Toddlers
Content reviewed against published AAP, WHO, NICE, AAP guidelines
Last reviewed:
Dehydration occurs when a baby loses more fluid than they take in. Babies are at higher risk of dehydration than older children due to their higher body water content, larger surface area relative to weight, and faster metabolic rate. The most common causes are vomiting and diarrhea from gastroenteritis. Key signs include decreased wet diapers, dry mouth, no tears when crying, and sunken fontanelle.
Key takeaways
- Dehydration occurs when a baby loses more fluid than they take in.
- Most common cause: Viral gastroenteritis (vomiting and/or diarrhea)
- Emergency: No wet diaper for 8+ hours in an infant
- Home care: Offer oral rehydration solution (Pedialyte) in small, frequent sips — 1-2 teaspoons every 5 minutes
Possible Causes
When to Seek Help
Emergency — Call 911 or go to ER:
- No wet diaper for 8+ hours in an infant
- Baby is lethargic, limp, or unresponsive
- Sunken fontanelle with dry mucous membranes and no tears
- Skin stays "tented" for more than 2 seconds when gently pinched
- Cold, mottled, or blue extremities with rapid heart rate
- Baby unable to keep any fluids down for 8+ hours
- Rapid breathing with dehydration (possible metabolic acidosis)
Urgent — See doctor today:
- Fewer than 3 wet diapers in 24 hours
- No tears when crying with dry mouth
- Sunken eyes in a sick child
- Baby drinking less than half of normal and wet diapers decreasing
- Persistent vomiting and diarrhea with child unable to catch up on fluids
- Newborn not feeding well with decreasing wet diapers
Same-day appointment:
- Mildly reduced wet diapers (4-5 instead of usual 6+) with baby still drinking
- Mild dry mouth during illness but baby accepting oral rehydration
- Concern about inadequate breastfeeding and possible dehydration in newborn
Monitor at home:
- Baby with vomiting or diarrhea but maintaining wet diapers and accepting fluids
- Mild illness with slightly reduced intake but at least 4-6 wet diapers per day
- Baby in warm weather drinking slightly more than usual (appropriate response)
By Age
0-3 months
Normal: Newborns should have at least 6 wet diapers per day after day 4 of life. In the first 3 days, fewer wet diapers are normal as milk comes in. Stool frequency varies but should be at least 3-4 per day in the first weeks.
Worry if: Fewer than 4-6 wet diapers per day, no wet diaper for 6+ hours, dry mouth, sunken fontanelle, weight loss more than 10% of birth weight, or baby too sleepy to feed. Newborn dehydration can progress rapidly.
3-12 months
Normal: Normal urine output is 4-6 wet diapers per day. Slightly less output during a mild illness with recovery within 24 hours can be managed at home if baby is still drinking.
Worry if: Fewer than 3 wet diapers in 24 hours, no tears when crying, dry sticky mouth, sunken eyes, lethargy, skin that stays "tented" when pinched, or baby unable to keep any fluids down.
1-3 years
Normal: Normal urine output varies but child should be urinating at least 3-4 times per day. Slightly less intake during mild illness with return to normal within 48 hours is common.
Worry if: No urine for 8+ hours, dry mouth with cracked lips, sunken eyes, crying without tears, listlessness, cold/mottled hands and feet, rapid heart rate, or excessive thirst followed by refusing fluids.
Any age
Normal: Mild dehydration (slightly reduced wet diapers, mildly dry mouth) can often be managed with oral rehydration at home if child is still able to drink.
Worry if: Moderate to severe dehydration: no tears, sunken eyes/fontanelle, skin tenting, lethargy, rapid heart rate, cold extremities. Severe dehydration is a medical emergency requiring IV fluids.
Home Care
- Offer oral rehydration solution (Pedialyte) in small, frequent sips — 1-2 teaspoons every 5 minutes
- For breastfed babies: nurse more frequently and for shorter periods
- If baby vomits, wait 20-30 minutes then restart with smaller amounts
- Do NOT give plain water to babies under 6 months (risk of water intoxication)
- Avoid juice, soda, and sports drinks — too much sugar can worsen diarrhea
- Pedialyte popsicles for toddlers who refuse to drink
- Track wet diapers on paper — write down time of each wet diaper
- Weigh baby if possible (using kitchen scale for newborns) to track fluid status
- Continue age-appropriate foods alongside rehydration fluids — do not restrict diet
- Cool room temperature — avoid overheating which increases fluid losses
Need help deciding what to do?
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Sources
All content follows our editorial policy and is reviewed against published clinical guidelines.
2,705 evidence-based guides6 authoritative medical sources
Related Symptoms
Bottom line
Most cases of dehydration in babies are not emergencies. However, seek immediate care if no wet diaper for 8+ hours in an infant.
Trust your instincts. If something feels wrong, reach out to your pediatrician. Worrying about your baby means you care — that is a good thing.