Why is my baby’s skin yellow?

Jaundice is a common condition in newborns that causes the skin and the whites of the eyes to turn yellow. Jaundice is caused by excess bilirubin in the blood which is produced by the liver when it processes old red blood cells. Treatment of jaundice depends on the specific cause and the level of bilirubin. Most jaundice is called physiologic jaundice, is harmless, and is gone within three to five days after birth. Some healthy breastfed babies continue to be jaundiced after one week of age (breast milk jaundice). It is not a reason to stop breastfeeding. If jaundice appears very soon after birth, is severe, or lasts longer than two weeks, babies should have their blood tested. Jaundice can happen when a newborn baby does not take in enough milk, has a genetic condition, or is premature. A small number of babies such as those who are very underfed, have very high levels of bilirubin which can cause severe short- and long-term brain damage.

A) Describing jaundice

A newborn whose jaundice was caused by not taking in enough milk after birth.

The word jaundice comes from “jaune,” the French word for yellow. When babies get jaundice, their skin and the whites of their eyes become yellow.

Jaundice is usually first seen on the face, then the chest, tummy, arms, and legs. It may be harder to assess in babies with darker skin. With these babies, checking the eyes, gums, and inner lips may help to identify jaundice.

Jaundice is caused by excess bilirubin in the blood. Bilirubin is made by the body as it processes old red blood cells. The liver then processes the bilirubin by mixing it with an acid that converts it from an uncombined form to a combined form. This combined form then leaves the liver, enters the gut, and then leaves the body in the stool (poop).

Blood tests to measure the amounts of uncombined and combined bilirubin can help health-care providers see how much bilirubin is in the baby’s blood and find the cause of the jaundice. Bilirubin levels can also be measured by devices that measure the amount of yellow in a baby’s skin but blood tests are more accurate.

Tests are done if the jaundice appears very early after the baby's birth, is severe, or lasts longer than two weeks.

Very high bilirubin levels can cause severe short- and long-term brain damage (kernicterus). This is believed to affect 1 in 200,000 babies in high-income countries and more in lower-income countries (Flaherman 2017).

Please consult your health-care provider if you notice your baby is jaundiced.

B) Physiologic jaundice

Most jaundice is physiologic (to do with the normal working of the body) jaundice and is harmless. It may even have health benefits (Hansen 2018).  

Physiologic jaundice is thought to occur in 85% of normal babies (Slusher 2017). It may develop because newborns:

  • Have blood cells that don’t live as long and are more concentrated than those of adults.
  • Are slower to process bilirubin, because their livers are immature.
  • May have delayed stooling of meconium (the first poop), which allows bilirubin to re-enter the system.

Physiologic jaundice is most noticeable when the baby is two to four days old and is usually gone within one week after birth.

C) Breast milk jaundice

Some healthy breastfed babies continue to be jaundiced after one week of age. This is called breast milk jaundice. At 2 weeks, 2% to15% of normal breastfed newborns are still jaundiced (Fawaz 2017). Breast milk jaundice may continue for two to three months and rarely needs treatment. It is not a reason for stopping breastfeeding.

The reason some breastfed babies stay jaundiced is not known, but most theories involve:

  • The amount of bilirubin that returns to the baby’s system from the gut.
  • Agents in breast milk.
  • Differences in the gut bacteria (microbiome) (Li 2020; Zhou 2019).

If jaundice lasts longer than two weeks, babies should have their blood tested to make sure there is not a disease causing the jaundice.

D) Breastfeeding failure jaundice

Newborns who do not get enough milk can develop jaundice. This has several names, including breastfeeding failure jaundice and starvation jaundice (Flaherman 2017). Premature and early-term babies are at higher risk.

In addition to treating their jaundice, these babies need immediate feeding. Any breastfeeding problems need to be identified and fixed if possible. They often need treatment with milk supplements. Once the babies are adequately fed, the jaundice does not return.

E) Other causes of jaundice

There are many other causes of jaundice, including:

  • The baby's blood cells being damaged by the mother’s antibodies (for example, ABO incompatibility or Rh disease)
  • Major bruising from labour or delivery
  • Prematurity
  • Infections
  • Genetic conditions (Boo 2020; Weng 2018)
  • Blocked bile ducts in the liver (biliary atresia)
  • Low thyroid hormone levels in the baby

F) Treating jaundice

The treatment of babies with jaundice depends on the cause and the bilirubin levels. Jaundice may have more than one cause. Each needs to be diagnosed and treated as appropriate.

High bilirubin levels are often treated by exposing the baby to coloured light (phototherapy) delivered by lights or blankets. There is no need to stop breastfeeding when a baby is receiving phototherapy (Barrington 2016).

In rare cases, babies need more aggressive treatment such as exchange transfusions, in which some blood is removed and replaced by donated blood. Such babies may be too ill to breastfeed.

In every situation, make sure your baby is getting enough milk, ensure that you maintain your milk supply by effective breastfeeding or expressing, and work closely with your health-care providers. Breastfeeding specialists can be very helpful in this situation (Kovaric 2020).


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Boo NY, Sin S, Chee SC, et al. Genetic Factors and Delayed TSB Monitoring and Treatment as Risk Factors Associated with Severe Hyperbilirubinemia in Term Neonates Admitted for Phototherapy. J Trop Pediatr. 2020 Jun 24:fmaa016 

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Kovaric K, Cowperthwaite M, McDaniel CE, et al. Supporting Breastfeeding in Infants Hospitalized for Jaundice [published online ahead of print, 2020 May 6]. Hosp Pediatr. 2020;hpeds.2020-0056

Li Y, Shen N, Li J, et al. Changes in Intestinal Flora and Metabolites in Neonates With Breast Milk Jaundice. Front Pediatr. 2020;8:177

Slusher TM, Zamora TG, Appiah D, et al. Burden of severe neonatal jaundice: a systematic review and meta-analysis. BMJ Paediatr Open. 2017 Nov 25;1(1):e000105
Weng YH, Cheng SW, Yang CY, et al. Risk assessment of prolonged jaundice in infants at one month of age: A prospective cohort study. Sci Rep. 2018 Oct 4;8(1):14824

Zhou S, Wang Z, He F, et al. Association of serum bilirubin in newborns affected by jaundice with gut microbiota dysbiosis. J Nutr Biochem. 2019 Jan;63:54-61