A baby's nappy can go wet for 2-3 hours during the day, or up to 12 hours at night with overnight diapers, but frequent changes (every 3-6 hours, or with poop) are best to prevent rash, especially for newborns who need more frequent changes (every 1-3 hours). Don't leave a dirty diaper on too long, but a dry one doesn't always need changing unless there's a routine or skin concern, with night-time diapers allowing longer wear.
Call your doctor if your baby or child has a dry mouth, fewer tears than usual, and no wet diapers or hasn't urinated in more than 6 hours.
Nappies – when to worry about dry nappies
Regular wet and dirty nappies show that your baby is feeding well and is healthy. If your baby has fewer wet or dirty nappies than usual, speak to your GP or midwife. If your baby has had no wet nappy for 12 hours, seek medical advice right away, as they may be dehydrated.
12 hours is too long without a wet diaper, even for a breastfed baby. They should have at least 6 a day, so every few hours. You should call the doctor and look for any other signs of potential dehydration.
However, once breastfeeding or formula feeding is well-established, newborns usually have at least six wet diapers daily. If a newborn goes more than 4 to 6 hours without peeing, it's important to monitor for other signs like dry lips, lethargy, or sunken eyes, as these could indicate dehydration.
The "21-second pee rule" comes from a scientific study showing most mammals over about 3 kg (6.6 lbs) empty their bladders in roughly 21 seconds, a phenomenon explained by physics where longer, wider urethras in larger animals use gravity to maintain a similar flow rate to smaller ones, and it serves as a loose benchmark for human bladder health; significantly shorter or longer times can signal issues like overactive bladder or holding it too long.
A wet diaper is as heavy as 3 tablespoons of water. Poop can look seedy. Only count poops larger than this. Babies make some large and some small poops every day.
Of course, if your newborn is still not peeing after a fever breaks or a heat wave has passed, when no illness persists, or after feeding, contact your child's healthcare provider ASAP, especially if your baby doesn't pee at all within a span of six to eight hours.
When to Take Your Child to the Emergency Room?
Signs and Symptoms of Dehydration in Babies and Children
Sunken eyes. Dark yellow wee, or no wee in the last 12 hours. More dry nappies than usual. Sunken fontanelle (the soft spot on your baby's head)
It can be confusing to determine the difference between Newborn and 0-3 month clothes, but typically Newborn sizes cover babies in the 5-8 pound range while the 0-3 month sizes fit 8-12 pound children.
Signs of dehydration in a baby may include:
The 7 key danger signs for newborns, often highlighted by organizations like the WHO, are not feeding well, convulsions, fast breathing, severe chest indrawing, lethargy/unconsciousness (movement only when stimulated), high or low temperature, and jaundice (yellow skin/soles) or signs of local infection like an infected umbilical stump, requiring immediate medical attention.
If you notice your baby constantly waking up with dry diapers, make sure they're getting enough fluids throughout the day. Offer frequent feedings and sips of water. Watch for other signs of dehydration like dry mouth, sunken eyes, or fewer wet diapers during the day. If you have concerns, consult your pediatrician.
The best liquid for dehydrated kids is an oral rehydration solution, like Pedialyte® and Enfalyte® (and many stores also have a store brand). It has the right amounts of water, sugar, and salt to help with dehydration. You can buy it without a prescription at drugstores or supermarkets.
If your child has severe dehydration
If your baby or child is severely dehydrated they may need to go to hospital for treatment and stay overnight. In hospital, a drip may be placed into a vein in your child's arm, hand or foot to give them fluids. Sometimes, a feeding tube is placed in your child's tummy.
It takes a period of more than 24 hours to enter severe dehydration, though Vrablik notes it takes less time if you are losing fluid because you are sweating. “As your kidneys shut down the rest of your body starts to suffer: your brain, liver and, eventually, your heart,” Vrablik says.
Acute urinary retention is considered an emergency, so you should seek immediate care if your child hasn't been able to urinate or fully empty their bladder for 12 hours or more.
WHEN TO GO TO THE ER. If your child is having signs of dehydration such as less than 3-4 wet diapers in 24 hours, or few to no tears when crying, or dry/cracked lips and lethargic.
The 5-3-3 rule is a loose guideline for structuring a baby's sleep schedule: 5 hours of wake time before the first nap, 3 hours of wake time before the second nap, and 3 hours before bedtime.
In babies younger than 6 months, look for fewer than six diapers per day or little to no urine in 4 to 6 hours. In toddlers, look for little to no urine over the course of 6 to 8 hours. Loss of energy: Dehydration can also cause lethargy, listlessness, lack of concentration, fussiness, and paleness.
The hardest week with a newborn is often considered the first six weeks, especially weeks 2-3, due to extreme sleep deprivation, constant feeding demands, learning baby's cues, postpartum recovery, and a peak in inconsolable crying (the "witching hour"), making parents feel overwhelmed as they adjust to a new, exhausting routine. While the first week is tough, the challenges often intensify as the baby becomes more alert but still fussy, with major developmental hurdles like cluster feeding and increased fussiness peaking around 6-8 weeks.
The "3 poop rule," or "three-and-three rule," is a guideline for normal bowel habits, suggesting that pooping anywhere from three times a day to three times a week is considered healthy, with individual patterns varying widely. It helps identify issues: fewer than three times a week may signal constipation, while more than three times a day (especially with loose stools) might indicate diarrhea, prompting a doctor visit for persistent problems, notes Symprove UK.
It therefore stands to reason that breastfed newborns pee less frequently— sometimes only 2 or 3 times a day—and in much smaller amounts until their mothers' full-volume milk supply comes in (typically 2 to 5 days after delivery).