Causes and types of jaundice explained

Jaundice is a common newborn condition, affecting about 60 percent of full-term infants and 80 percent of preterm infants in the first week of life. You will know your baby has jaundice if his skin and the whites of his eyes appear yellow, although a blood test can reveal just how jaundiced he is. Although jaundice sounds scary, in most cases it is simply a sign that your baby is adjusting to life outside the uterus. Newborn jaundice is usually mild and seldom requires treatment, but it does require evaluation and follow-up with your baby’s health care provider.

What causes jaundice?

When babies are inside the uterus they need extra red blood cells to meet their oxygen needs. After birth, these extra cells break down, releasing a substance called bilirubin. The liver filters bilirubin from the blood and excretes it in stool. It takes several days or weeks (even longer in preterm babies) before a newborn’s liver functions fully. In the meantime, it can be hard for babies to get rid of the bilirubin that collects after birth. Low levels of bilirubin are safe, but prolonged high levels may cause brain damage if left untreated. So babies with jaundice should be carefully monitored and treated if their bilirubin levels get too high. 

Your baby’s first stools consist of meconium, a black, sticky substance that contains, on average, 450 mg of bilirubin (a lot!). Colostrum, the first milk a mother’s body makes, acts as a natural laxative to cause the passage of meconium. Frequent breastfeeding results in frequent stools (infant formula lacks this special laxative). Practices that interfere with breastfeeding—separation of mother and baby, rigid feeding schedules (as opposed to 8-12 or more feedings in each 24 hours), lack of skin-to-skin contact, early use of pacifiers, and poor positioning or latch (limiting milk transfer)—result in fewer breast feedings, fewer stools, and a greater risk for worsening jaundice.

Types of jaundice 

When babies breastfeed effectively, there is little chance of severe jaundice, but all parents need to be aware of the different types of jaundice. 

  • Pathologic jaundice. Pathologic jaundice is the most serious type of jaundice. It occurs within 24 hours after birth, and is characterized by a rapid rise in a baby’s bilirubin level. The most likely cause is blood incompatibility or liver disease. Prompt medical attention is necessary, and blood transfusions may be required. Breastfeeding can continue during treatment.
  • Physiologic (neonatal) jaundice. Physiologic jaundice usually appears at day 2-5 and lasts about 10–12 days. The best treatment for physiologic jaundice is frequent and effective breastfeeding—at least 8-12 or more times in each 24-hour period. Giving water, glucose water, or formula supplements won't help because they lack the laxative effect of colostrum. Instead, they can interrupt development of the mother's milk supply and increase the risk of weaning.
  • Breast milk jaundice. Although breast milk jaundice is quite rare, it often causes concern in part because why it happens is unclear. There may be differences in the infant’s reabsorption of the bilirubin, or in the mother’s milk. Breast milk jaundice can appear 2-5 days after birth. Bilirubin levels peak around 10–14 days, but they may remain high for several weeks, even as much as 3 months. If the bilirubin level continues to climb, your baby’s health care provider may suggest supplementing your breastfeeding with your own milk, donor breast milk, or formula until jaundice resolves. In rare cases, breastfeeding may be interrupted for 24 hours, in an effort to reduce the bilirubin level. (If this course of treatment is followed, mothers should pump their milk to maintain their milk supply.) Because these options can interfere with breastfeeding, discuss the benefits and the risks with your baby’s health care provider before making a final decision.  
  • Suboptimal intake jaundice. Formerly called “breastfeeding jaundice,” or “lack of breastfeeding jaundice,” or even “starvation jaundice,” this is caused by infrequent or ineffective breastfeeding. The Academy of Breastfeeding Medicine (ABM) says it is the result of too little breastfeeding (from breastfeeding difficulties or a delay in milk production) and therefore low caloric intake, combined with limitations in bilirubin metabolism and transport. All of this can cause bilirubin levels to be higher in the baby’s blood. Formula feeding is no “cure-all” for this kind of jaundice; the key is to make sure your child is taking in enough calories. Often, this resolves once the mother’s milk supply improves when her baby is around 2-5 days of age. Skin-to-skin care and frequent breastfeeding can help, as the ABM explains, “with milk supply and makes mother’s milk easily available to the infant.” To ensure that your breastfeeding baby is transferring milk, listen for sounds of suckling and swallowing.

Preventing jaundice 

The best way to prevent jaundice is to breastfeed your baby early and often—as soon as possible after birth (ideally within the first hour, even if you have a cesarean section) and at least 8 to 12 times in each 24-hour period. Respond to your baby’s early signs of hunger; do not wait for your baby to cry, as that is a late sign of hunger and may actually interfere with effective feeding.  

Avoid supplementation with water, glucose water, or infant formula. Do not supplement with expressed milk, donor milk, or formula unless there is a medical reason (such as weight loss of more than 10 percent after attempts to correct breastfeeding problems, failure to produce or transfer breast milk, or evidence of dehydration). Generally, as long as phototherapy is available, supplementation is not necessary. And if you must supplement, be sure to pump so that your milk supply is not negatively affected.

You'll know your baby is getting enough to eat if you see three or more stools a day by day 3. Your baby’s stool will be black (meconium) on days 1 and 2; green (transitional) on days 3 and 4; and yellow (normal) by day 5. If you continue to see black stools on day 3 or green stools on day 5, call your baby’s health care provider right away. This could be a sign that your baby isn’t getting enough to eat. To learn about how what your baby's poop can tell you about their health, click here

Your newborn will be screened for signs of jaundice before leaving the hospital. If signs of jaundice appear after returning home from the hospital with your baby, immediately contact your baby's health care provider.

Last updated March 17, 2023

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