Urate Crystals

New parents are sometimes concerned to find dark pinkish-orange spots in their intact baby’s diaper during the first few days of life, and worry it might be blood the baby’s urine. In almost all of these cases, however, the substance that looks remarkably like blood in a diaper is actually not blood at all, but rather what is known as urate crystals.*

The appearance of urate crystals – sometimes referred to as “brick dust” or “brick powder” (since it turns to powder if left to dry) or “pink diaper syndrome” – results from a high concentration of uric acid. This transient occurrence is common for boys and girls in the first few days of life, particularly if they are breastfed. A quick Google Image search for “urate crystals in diaper” can provide a visual to compare with your son’s diaper. (Note: Urate crystals appearing beyond the first few days after birth or appearing repeatedly in the diapers of a newborn can warrant an evaluation to ensure the baby is transferring milk effectively and eating often enough.)

A breastfeeding parent produces very small, concentrated amounts of colostrum until beginning the transition to larger volumes of mature milk around the second or third day (sometimes this can take a little longer). On day one of life, a baby consumes about 1-2 teaspoons of colostrum per nursing session, one of the many reasons newborns nurse so frequently. Colostrum is extremely important during this time, as it contains exactly the correct mix of nutrients and immune factors for a brand-new baby. But it’s essential to note that colostrum is supposed to be produced and consumed in these tiny amounts – this is physiologically normal. The low total fluid volume and high protein content of colostrum contribute to the formation of urate crystals. If any crystals are seen, they should clear quickly as the baby begins to consume larger volumes of transitional breast milk around day three and urine output increases.

It is important for parents of intact newborn boys to be knowledgeable about urate crystals so a baby can remain safe if professional breastfeeding/medical evaluation is sought for urate crystals visible beyond day three or at several diaper changes. Many healthcare providers in the United States are still unfamiliar with foreskin functions and care. If a particular provider is also unfamiliar with urate crystals and their causes, a baby can wind up receiving incorrect treatment, including forced retraction, catheterization, or antibiotics. Parents can be aware that urate crystals are not caused by infection, and thus prevent a son from experiencing unnecessary and harmful medical interventions.

*Sometimes in the first few days of an intact infant girl’s life, she may have some true bloody discharge appear in her diaper as a result of having been in contact with her mother’s hormones while in utero. This is also normal. After an infant has been circumcised, there is a risk of bleeding/hemorrhaging from the circumcision site, and diapers need to be closely monitored.


Lauwers, J., & Swisher, A. (2016). Counseling the Nursing Mother: A Lactation Consultant’s Guide (6th ed.). Burlington, MA: Jones and Bartlett Learning.

Penchuk, E. (2004, December). The Importance of Colostrum. Retrieved from http://www.llli.org/llleaderweb/lv/lvdecjan05p123.html

 Rennie, J.M. (2012). Hormonal effects in newborns. Retrieved from http://pennstatehershey.adam.com/content.aspx?productId=117&pid=1&gid=001911

 What is colostrum? How does it benefit my baby? (2016, January). Retrieved from https://www.llli.org/faq/colostrum.html