Urate Crystals in a Baby's Diaper

What they are and what to do

Mother changing baby's diaper

Science Photo Library - RUTH JENKINSON / Brand X Pictures / Getty Images

If you've noticed a reddish-orange stain on your baby's diaper, it's understandable to worry that it is blood. However, what you're seeing is likely urate crystals in your newborn's diaper. While it's important to make sure it isn't blood, the brick-colored stain of urate crystals is common, and usually harmless, in newborns.

Typically, urate crystals in a diaper have a drier, thinner texture and color than blood. Learn more about what urate crystals in a diaper are, why they might appear in your newborn's diapers, and when they could be a reason for concern.

What Are Urate Crystals in a Diaper?

Urate crystals have an orange or red brick color and look like a stain over the urine in a diaper. They may have a thin, chalky texture, Typically, blood has a more vivid red color and a more viscous, thicker consistency. Blood also smells metallic while urate crystals smell like urine.

Though they might be scary, seeing urate crystals in a diaper is very common. They do not harm your baby and do not indicate anything dangerous is going on. They are most prevalent in breastfed babies. Approximately 22% of breastfed newborns have urate crystals in their diapers during the first week of life.

Urate crystals are especially common during a baby's first few days when they might still be losing weight (losing weight is normal and expected at this time). Urate crystals may be found in babies who are gaining weight as well.

What Causes Urate Crystals?

Urate crystals are a by-product of concentrated urine. They are made up of uric acid, an end product of normal metabolism. Babies are born with a high blood uric acid level because of the amount they get across the placenta, and this is quickly excreted in the urine and stool.

If a baby is not making much urine at this time, these urate crystals will be especially concentrated and easy to see. This does not mean, however, that your baby is dehydrated.

What to Expect in a Newborn's Diaper

During a breastfed baby's first five days, the number of wet diapers should match your baby's day of life (so two wet diapers on day two, three wet diapers on day three, and so on). It can take up to four days (or sometimes even longer) for breast milk to come in, and once it does your baby's diaper count will likely go up.

On day two, expect at least two wet diapers and two bowel movements that are likely still thick, tarry, and black (meconium). On day three, a baby should have at least three wet diapers and three bowel movements, with the bowel movements becoming looser and greenish to yellow in color (transitional stools). By day five, expect at least five wet diapers and five yellow, soft, and watery bowel movements.

If your baby is having fewer wet diapers than expected, get your baby evaluated by a pediatrician right away to check their weight and to see if they are feeding well.

When breastfeeding, a lactation consultant can evaluate your milk supply and make sure your baby is latching on and sucking well. If your baby is on infant formula, check that you are preparing it correctly and that they are eating enough each day.

When Urate Crystals Indicate a Problem

Most of the time, urate crystals in a baby's diaper in the first week of life are normal. During this time the crystals are harmless, a problem only because they can cause parents to fear there is a something wrong or newborns must undergo unnecessary tests looking for blood in the urine.

However, urate crystals that persist for longer than three days can be a sign of dehydration or an indication that a baby is not getting enough milk. Talk to your physician or lactation consultant to help ensure that your baby is eating enough and is well hydrated.

Rarely, urate crystals, especially those present in a child beyond the first week of life, could signify a serious condition such as kidney dysfunction or other metabolic disorders which result in hyperuricemia. Consult your baby's pediatrician if you have any concerns or questions about seeing urate crystals in your baby's diaper.

A Word From Verywell

While it can be unnerving to see a pink, red, or orange stain in your newborn's diaper, most of the time it is harmless urate crystals, not blood. As long as your baby is feeding well and not showing signs of dehydration, you do not need to worry about urate crystals.

But if you ever have questions or concerns about your baby's care or health, it is always appropriate to contact a healthcare provider. They are there to help.

6 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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  2. Rhodes PG, Hammel CL, Berman L. Urinary constituents of the newborn infantJ Pediatrics. 1962;60(1):18-23. doi:10.1016/s0022-3476(62)80003-1

  3. Jeng JY, Franz WB. Orange stains in a healthy neonate's diaper. Clin Pediatr (Phila). 2014;53(9):908-10. doi:10.1177/0009922814536777

  4. Johns Hopkins Medicine. Breastfeeding.

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  6. Mujawar NS, Jaiswal AN. Hypernatremia in the neonate: Neonatal hypernatremia and hypernatremic dehydration in neonates receiving exclusive breastfeeding. Indian J Crit Care Med. 2017;21(1):30-33. doi:10.4103/0972-5229.198323

Additional Reading
  • Amin R, Eid L, Edvarsson V, Fairbanks L, Moudgil A. An unusual cause of pink diaper in an infant. Pediatric Nephrol. 2016. 1(14):575.

  • Kliegman RM, Stanton B, St Geme III JW, et al. Nelson Textbook of Pediatrics, 20th ed. Elsevier.

By Vincent Iannelli, MD
Vincent Iannelli, MD, is a board-certified pediatrician and fellow of the American Academy of Pediatrics. Dr. Iannelli has cared for children for more than 20 years.