Appearance of Urate Crystals in a Baby's Diaper

Mother changing baby's diaper

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If you've noted a reddish-orange stain on your baby's diaper, you may be feeling panicky thinking that it's blood. While it's important to make sure it isn't blood, the brick-colored stain of urate crystals is a very common cause of this frightening finding in newborns. What exactly are urate crystals and why do they occur? When could they be a reason for concern?

Urate Crystals in a Diaper

It is not uncommon to find urate crystals, which have an orange or red, brick dust color, in a newborn baby's diaper, even cloth diapers. Unfortunately, this appearance can easily be mistaken for blood, leaving parents anxious and worried.

Though they might be scary, these crystals are very common. In fact, one older study found urate crystals in the urine of 64% of newborn babies. Of course, they aren't visible on a diaper that often.

Though they are a common cause of parental concern, and most commonly are a normal finding, urate crystals are not spoken of to the degree of many other findings in a newborn baby. Urate crystals are especially common during a baby's first few days of life when they might still be losing weight while breastfeeding (losing weight is normal and expected at this time). Urate crystals may also be found in babies who are gaining weight as well.

Causes of Urate Crystals

Urate crystals are most common in infants who are breastfed. During the first few days of life, breast milk contains colostrum, the wonderful fluid rich in immune factors and nutrition which makes breastfeeding so beneficial in boosting a newborn's immune function.

Urate crystals 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. Instead, you can make sure your baby is properly drinking and urinating enough with a few simple questions.

Ensuring That Your Baby Is Hydrated

During your baby's first five days, if you are breastfeeding, you should expect the number of wet diapers and bowel movements to match your baby's day of life. It can take up to four days (or sometimes even longer) for your milk to come in, and once it does your baby's diaper count will likely go up.

  • On day two: At least two wet diapers and two bowel movements that are likely still thick, tarry, and black (meconium)
  • On day three: At least three wet diapers and three bowel movements, with the bowel movements becoming looser and greenish to yellow in color (transitional stools)
  • On day five: At least five wet diapers and five yellow, soft and watery bowel movements on day four

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

When breastfeeding, a lactation consultant might be helpful to evaluate your milk supply and make sure your baby is latching on and sucking well. If your baby is being fed baby formula, then you should make sure that you are preparing it correctly and that they are eating enough each day.

A Word From Verywell

Most of the time, urate crystals in a baby's diaper in the first three days of life are normal in a breastfeeding infant. During this time the crystals are harmless, a problem only because they can cause parents to fear there is a problem or undergo unnecessary tests looking for blood in the urine of their newborn.

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. Talking to your physician or lactation consultant can help you get to the bottom of this.

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.

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Article Sources
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  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., and A. Moudgil. An Unusual Cause of Pink Diaper in An Infant. Pediatric Nephrology. 2016. 1(14):575.
  • Kliegman, Robert M., Bonita Stanton, St Geme III Joseph W., Nina Felice. Schor, Richard E. Behrman, and Waldo E. Nelson. Nelson Textbook of Pediatrics. 20th Edition. Philadelphia, PA: Elsevier, 2015. Print.