Finally, Newborn Jaundice Explained! (Pedcast)


Dr Paul Smolen here, your host for pediatric talk.

Thank you for joining me today for the next installment of your pediatric education.

From diapers to the degree… we have useful information for parents.  Knowledge is power.

So sit back and soak in the power of understanding with today’s topic of newborn jaundice.

What is jaundice and why do babies get it?  This is what we are going to tackle in today’s pedcast.


Let’s start by talking a little science talk with a trip down science lane.

I think once you understand what bile is and how your child’s little body processes it, you will have a good handle on newborn jaundice.

So bear with me, this is a LITTLE complicated but I am sure you are up to it.

Jaundice is what we call it when bile backs up into our blood in abnormal quantities.

When your child breaks down old blood, specifically the red stuff called hemoglobin inside red blood cells, his or her liver converts the used hemoglobin into bile.

Bile is actually a waste product of our body, very much like stool or urine.

It must be excreted and eliminated from your newborns body otherwise it can back up and cause problems.

Bile is a bright green liquid that gets stored in your child’s gallbladder tucked nice and neatly under their liver.

Bile is a detergent of sorts, being squirted into your child’s intestine to help digest fats when they come down the river of food that is moving through your baby’s intestines.

Bile is bright green when it leaves the liver and gallbladder but changes colors as it moves through our intestines, first to a yellow color and finally to a brown color.


And one more fact you need to understand about bile…which is that as it passes through our skin and is exposed to ultraviolet light, it is chemically converted into a water soluble substance which can be removed from the body through urine.

So remember, bile is a waste fluid that needs to be eliminated from your newborn’s body otherwise it will back up in the blood in large amounts causing a dangerous situation called severe jaundice.

While most of the bile is excreted through the gut in as part of stool a little can be excreted through urine, especially if your baby is exposed to natural sunlight or phototherapy in the hospital.


Before your child is born, mom’s liver did all the recycling of blood for the infant …but then comes birth and everything changes.

The cord is cut and your on your own baby when it comes to metabolism.

Not only does the baby need to make bile to recycle their old blood but they need to get rid of it.

That’s hard with a substance that is not water soluble when you live in a body that is 90% water.

Unless your child is exposed to ultraviolet light, bile can’t go out through the kidneys because they are all about water.

The only other way out is the long way through their intestines.


So babies are born with a big dilemma.  They have to quickly learn how to both make bile and get rid of it, having never done so before.

And if too much bile backs up into the blood there is a potential that it can make a newborn sick from severe jaundice.

Talk about pressure.

Most babies are up to the challenge and quickly master the whole bile/ jaundice thing.

We call it jaundice when bile backs up in the system an starts showing up in the blood.

If jaundice develops in a older child or adult it usually signals disease but not usually in an newborn.

Almost all newborns develop a small amount of jaundice in the first week of life…  this is part of the normal transition after birth.



So now that you understand where bile comes from ( old recycled blood) and how your body gets rid of it (by mixing it into stool and excreting it that way, you can understand some other issues related to bile.

Babies that deliveries where they get bruise…more old blood to get rid of… tend to have more trouble with jaundice in the first week of life.

Babies who have a different blood type from their mother’s and experience an immune reaction that frees more hemoglobin into their circulation can have problems for the same reason… too much old blood to recycle and therefore a lot of bile in the blood.

Babies who have a liver infection called hepatitis have trouble making and secreting bile into the intestines…backing up into the blood again.

Babies with very poor calorie intake in the first week have very little poop moving through their intestines have no way to get rid of bile, so again…backing up into the blood once again.



The nurses and doctors who care for newborns are very attuned to watching for and dealing with jaundice in newborns.

Many babies have their bilirubin ( a pigment in bile) level measured in the first few days of life to guard against too much bile backing up into the circulation.

If our pediatrician gets worried, he or she may recommend that phototherapy with ultraviolet lights will help lower the bilirubin levels… and now you know why!

Increasing your baby’s calorie intake will also enhance your baby’s ability to get rid of bile… and now you know why that is as well.

See how much you have learned… amazing.

One other thing you need to know which is that premature babies and children who are born ill are much more prone to problems with jaundice so your child’s doctor will be even more vigilant about jaundice should you have either a premie or a child who is sick as a newborn.



I hope that quick run through the topic of jaundice de-mystifies that subject for you.

As always, your comments are welcome on the blog.  I try and answer them personally.

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This is Dr Paul Smolen, your pedcast host, broadcasting from studio 1E hoping you break out in a smile, the next time you think about bile.

Until next time.