By Bailey Pitcher, mom of two, current part time nurse and former ER nurse, balancing motherhood, family, and her passion for caring for others.
Wondering how jaundice and breastfeeding actually fit together, and whether formula is the fix? Here is what two Coombs positive babies and days of heel prick labs taught me about the question everyone asks at 2 a.m.
If you left the hospital with a yellow-tinged newborn and a stack of instructions about bilirubin, you are not alone. Jaundice shows up in roughly 4 out of 5 newborns, and it’s one of the most common reasons new parents get a crash course in blood tests, phototherapy, and, often, pressure to “just give a bottle so the baby will poop it out.”
I’ve been there twice. Both of my babies came back Coombs positive, which meant we were watching bilirubin numbers closely from day one. That meant seeing our pediatrician right away after leaving the hospital, then heading to the local children’s hospital for serial lab draws (heel prick testing) every day for several days in a row to track where the numbers were headed.
And both times, someone on the care team suggested formula as the fix. What I learned along the way is that jaundice and breastfeeding aren’t actually at odds, but there are a few things worth understanding so you can make an informed call with your pediatrician instead of just going along with whatever gets suggested in a tired 2 a.m. hospital room.
Why Newborns Get Jaundice in the First Place
Jaundice happens when a baby has more bilirubin in their blood than their liver can clear yet. Bilirubin is a yellow pigment created when red blood cells break down, something every newborn’s body is doing a lot of in the first days of life as they transition from womb to world. A newborn liver is still maturing, so it takes a little while to catch up, and in the meantime, bilirubin can build up and cause that telltale yellow tint to skin and eyes.
For most babies, this resolves on its own with time, feeding, and normal elimination. But some babies have factors that push their bilirubin higher or make it rise faster, which is where closer monitoring comes in.
What “Coombs Positive” Actually Means for Jaundice
A Coombs (or direct antiglobulin) test checks whether a baby’s red blood cells have been coated with antibodies from mom, usually because of an Rh or ABO blood type difference between mother and baby. If the test comes back positive, it means those antibodies are causing the baby’s red blood cells to break down a bit faster than usual, which produces more bilirubin, more quickly.
This is important context: a Coombs-positive baby’s jaundice isn’t caused by breastfeeding. It’s caused by red blood cell breakdown. That distinction matters, because it shapes what actually helps.
Breastfeeding Jaundice vs. Breastmilk Jaundice: Why the Labels Are Falling Out of Favor
You may hear two terms tossed around:
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“Breastfeeding jaundice” used to describe jaundice linked to a baby not yet taking in enough milk. Often in the first few days, while breastfeeding is still being established. Lower intake means fewer stools, and stooling is one of the main ways babies clear bilirubin from their bodies.
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“Breastmilk jaundice” used to describe a later, more prolonged jaundice in babies who are feeding and gaining weight well, thought to be related to a component in breast milk itself. It can last several weeks.
Here’s the more recent shift: the American Academy of Pediatrics’ updated 2022 hyperbilirubinemia guidelines “no longer risk-stratify patients based on whether the infant is breastfed or formula fed”, and pediatric researchers have specifically pushed to move away from the “breastfeeding jaundice” label altogether, in favor of describing what’s actually happening: a normal newborn transition that sometimes needs support and monitoring, rather than something breastfeeding is doing wrong.
What Actually Helps Jaundice: More Milk, Not Necessarily Different Milk
This is the part that surprised me the most. The instinct in a lot of hospital rooms is: baby is jaundiced, baby needs to poop more, give formula. But the research doesn’t point to formula being the fix, it points to volume and frequency of feeding.
A few things worth knowing:
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The AAP’s guidelines specifically recommend against giving newborns supplemental water or dextrose water to try to bring bilirubin down. It doesn’t help clear bilirubin and can interfere with a baby taking in adequate milk.
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If a baby genuinely isn’t transferring enough milk yet, which can happen in the first days for lots of reasons unrelated to jaundice, the priority is fixing intake: more frequent nursing (think 8 to 12 times in 24 hours), a lactation consultant checking latch and transfer, and weighing the baby to confirm they’re getting enough. Expressed breast milk is generally the preferred supplement if more volume is needed, with formula used when it’s medically indicated or expressed milk isn’t available.
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For a Coombs-positive baby specifically, more feeding still helps support elimination, but the real treatment lever for higher bilirubin from hemolysis is phototherapy, not a feeding switch. Phototherapy converts bilirubin into a form the body can clear more easily, and it works regardless of whether a baby is breastfed or formula fed.
In other words: if bilirubin is elevated enough to need treatment, the treatment is usually light, not formula. Formula might be layered in if there’s a separate, real concern about intake or weight loss, but that’s a different problem being solved, not a jaundice cure on its own.
The Bilirubin Monitoring That Actually Matters
What made both of our jaundice experiences manageable wasn’t switching to formula; it was tracking the numbers. A few things your care team may use:
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Transcutaneous or total serum bilirubin (TSB) levels, plotted against hour-specific nomograms that account for your baby’s age in hours, gestational age, and risk factors like a positive Coombs test.
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Weight checks, to confirm your baby is taking in enough regardless of feeding method.
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Wet and dirty diaper counts, as a rough at-home signal between appointments.
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Follow-up bilirubin checks, especially important for Coombs-positive babies since hemolysis can cause levels to keep climbing faster than in a baby without that risk factor.
What the Bilirubin Curve Actually Tells You
One thing that helped me stop panicking every time a new number came back higher than the last: bilirubin is expected to rise for the first several days of life. There’s a normal curve tied to hours of life, and what your doctor is watching for is whether your baby’s numbers are tracking along that expected curve, or climbing faster than expected for their age in hours. A rising number isn’t automatically an alarm; it’s the trajectory relative to the curve that matters. That’s exactly what our pediatrician was tracking with those daily heel pricks. Not just “is this number high,” but “is this number where we’d expect it to be, and is it slowing down the way it should.”
Our At-Home Plan for Jaundice and Breastfeeding
On our end, the plan alongside that daily monitoring was pretty simple: lots of skin-to-skin contact, latching and cluster feeding as often as our babies would take it, and keeping a close eye on wet and dirty diaper output between appointments. That combination, frequent feeding plus close professional monitoring of the actual curve, was what kept us out of the hospital both times, not a switch to formula.
If Phototherapy Is Needed
If your baby’s bilirubin does cross into a treatment threshold, phototherapy, sometimes at home with a portable biliblanket, sometimes in the hospital, is the frontline treatment, alongside continued breastfeeding. Exclusive breastfeeding and phototherapy are not mutually exclusive.
So. Does Your Baby Really Need Formula?
Not automatically, and not just because of a jaundice diagnosis. If your baby is transferring milk well, gaining appropriately, and stooling regularly, breastfeeding can continue right alongside whatever monitoring or phototherapy your pediatrician recommends. If intake genuinely is the issue, the first tools are usually more frequent nursing and lactation support, with expressed milk or formula as a next step if needed. A conversation to have with your pediatrician or IBCLC based on your baby’s actual numbers, not a blanket rule.
I’m not a doctor, and every baby’s situation is different, especially with something like a positive Coombs test in the mix. What I can tell you from having lived it twice, with numbers that came close enough to hospital admission both times, is that close outpatient follow-up of daily labs, a pediatrician who knew the expected curve, skin-to-skin, and frequent latching, was enough to keep us home and keep breastfeeding intact. It’s worth asking questions before assuming formula is the only path forward. “Can we keep breastfeeding while we monitor this closely?” is a completely reasonable thing to ask your care team, and for a lot of families, the answer is yes.
Always work with your pediatrician or a lactation consultant to monitor your baby’s bilirubin levels and feeding. This post is meant to help you ask informed questions, not to replace personalized medical care.
Jaundice and Breastfeeding FAQs
Does my jaundiced baby need formula?
Not automatically. If your baby is transferring milk well, gaining, and stooling regularly, breastfeeding can continue right alongside monitoring or phototherapy. Formula gets layered in when intake or weight loss is a separate, real concern, and that’s a decision to make with your pediatrician.
Can you keep breastfeeding during phototherapy?
Yes. Phototherapy works regardless of whether a baby is breastfed or formula fed, so exclusive breastfeeding and light therapy are not mutually exclusive.
Does breastfeeding cause jaundice?
No. Jaundice is bilirubin building up faster than a newborn liver can clear it, and for a Coombs positive baby it’s caused by red blood cell breakdown, not by breast milk. Low intake in the early days can slow bilirubin clearance, but the fix there is more milk, not different milk.
How often should I nurse a baby with jaundice?
Frequently. Think 8 to 12 times in 24 hours, plus lots of skin-to-skin, since stooling is one of the main ways babies clear bilirubin. If you’re unsure your baby is transferring enough, a lactation consultant can check latch and weigh before and after a feed.
Is it normal for bilirubin levels to keep rising?
Bilirubin is expected to rise for the first several days of life. What your doctor is watching is whether the numbers track along the expected curve for your baby’s age in hours, or climb faster than expected.
What does Coombs positive mean for jaundice and breastfeeding?
It means antibodies from mom are breaking down your baby’s red blood cells faster than usual, which produces more bilirubin, more quickly. It means closer monitoring and a real possibility of phototherapy. It does not mean you have to stop breastfeeding.