09/04/2026
More than 80% of newborn infants will have some degree of jaundice. Your breast milk isn’t “causing” your baby’s jaundice. 💛
Most newborn jaundice is called physiologic jaundice, which is caused by a buildup of a bilirubin in baby’s blood. Bilirubin is a yellow substance your body creates when red blood cells break down. While you’re pregnant, your liver removes bilirubin for your baby. But after birth, baby’s liver must begin removing bilirubin on their own. If baby’s liver is still immature, it may not be able to get rid of bilirubin fast enough. When excess bilirubin builds up, your baby’s skin may appear yellow. Bilirubin clears as baby POOPS. The more a baby p**ps, the faster jaundice can clear. And a baby p**ps because they are drinking milk. Jaundice is more common in breastfed babies than formula-fed babies. Formula is instant and in large volumes. Liquid in: p**p out. There’s nothing magic about formula to clear jaundice, it’s just…. There and ready to feed. Breast milk can be delayed for many reasons, like lots of fluids during labor and delivery, from a large blood loss, postpartum preeclampsia, an inefficiently feeding or sleepy baby, shallow latch or tongue tie
But there is another type called suboptimal intake hyperbilirubinemia, historically called “breastfeeding jaundice.”
This typically happens in the first several days of life when a baby isn’t getting enough milk. When milk intake is low, babies stool less, and bilirubin that would normally leave the body in the stool gets reabsorbed into the bloodstream. Excessive weight loss, dehydration and poor milk transfer can all contribute.
Notice what I said: the problem is inadequate milk intake, NOT breast milk itself.
Then there is breast milk jaundice, which is different.
Breast milk jaundice usually occurs later, often after the first week or two, in an otherwise healthy baby who is feeding well, hydrated, stooling and gaining appropriately. Bilirubin can remain elevated for weeks and sometimes even a few months.
The exact mechanism isn’t completely understood, but components of human milk appear to influence bilirubin metabolism and how much bilirubin is reabsorbed through the intestine.
And this is where things get really important:
The AAP does NOT recommend routinely stopping breastfeeding because a baby is jaundiced. For either breastfeeding OR breast milk jaundice.
Instead, we look at the whole baby.
How much milk is the baby actually transferring?
Are they having adequate wet and dirty diapers?
What is their weight trajectory?
Are they alert enough to feed?
Is the milk increasing in volume as expected? And is baby getting that milk?
And most importantly, what is the actual bilirubin level in relation to the baby’s age in hours, gestational age and other risk factors?
The AAP recommends supporting breastfeeding and feeding frequently in the newborn period, generally at LEAST 8 times in 24 hours. That’s the minimum.
If a baby isn’t getting enough milk, supplementation may sometimes be medically appropriate. Expressed breast milk, donor milk or formula can all be considered depending on the individual situation.
But a well-hydrated, adequately fed breastfed baby does not need to be automatically supplemented simply because they are yellow. Please don’t give water or sugar water to a jaundiced newborn. That is not recommended treatment.
Phototherapy, when needed, is based on the baby’s bilirubin level and risk factors, not whether the baby is breastfed or formula-fed. Breastfeeding can generally continue during phototherapy.
One more important piece:
If a breastfed baby is still visibly jaundiced at 3–4 weeks, the AAP recommends checking total AND direct/conjugated bilirubin. Persistent jaundice should not simply be dismissed as “breast milk jaundice” without making sure we aren’t missing another condition.
So when you have a yellow baby, don’t automatically hear:
❌ “Your breast milk is causing this.”
Instead, think:
💛 Yellow baby + inadequate intake → investigate feeding and milk transfer
💛 Yellow 1-2 week old baby + thriving, gaining and well hydrated → breast milk jaundice may be part of the picture
💛 Yellow baby + illness, significant risk factors, rapidly rising bilirubin or abnormal direct bilirubin → further medical evaluation is important
Jaundice and breastfeeding can coexist. One does not automatically mean you have to stop the other.
Treat the baby when treatment is needed, make sure they are getting enough milk, and support breastfeeding whenever it is safe to do so.
Let’s figure out why this baby is jaundiced AND support breast milk feeding. 💛
