Jaundice in Newborns: What It Is, When to Watch, and When to Act
By Christy Koraiban RN, BSN, LC | Every Baby Feeds
Your baby’s skin has taken on a yellow tint. Maybe the whites of their eyes look a little off. Your heart is in your throat.
Take a breath.
Jaundice is one of the most common conditions in the newborn period. It affects up to 60% of full-term babies — and the vast majority of cases resolve with close monitoring and, often, more feeding.
That doesn’t mean you ignore it. It means you understand it.
What Is Jaundice?
Jaundice is the yellowing of a baby’s skin and eyes caused by a buildup of bilirubin — a yellow pigment produced when red blood cells break down.
During pregnancy, your baby had extra red blood cells to carry oxygen from the placenta. After birth, those cells break down rapidly. The liver — still new to the job — has to process and clear the bilirubin through the stool. When it can’t keep up, bilirubin accumulates in the blood and shows up in the skin.
This is physiologic jaundice — a normal, expected process.
It’s not a sign that something went wrong. It’s a sign that your baby’s body is doing exactly what it was designed to do, just on a learning curve.
When Does Jaundice Typically Appear?
Timing is one of the most important factors your provider will assess.
Physiologic jaundice typically appears between day 2 and day 4 of life and peaks around day 3–5 in full-term babies. It then gradually improves over the first 1–2 weeks.
Jaundice appearing within the first 24 hours of life is not physiologic. This needs to be evaluated urgently. Early-onset jaundice can indicate an underlying condition like blood type incompatibility (ABO or Rh) and requires prompt medical attention.
This distinction — when the yellow appeared — matters more than many parents realize.
How Is Jaundice Assessed?
Your provider will check bilirubin levels either through a skin sensor (transcutaneous bilirubin) or a blood test (serum bilirubin). Results are interpreted using an age-in-hours nomogram — essentially a chart that accounts for how old your baby is and their individual risk factors.
A level that’s perfectly fine at 72 hours may look different at 36 hours.
This is why “it’s just jaundice” isn’t always the full picture — and why follow-up appointments in those early days exist for good reason.
You’re Home. It’s Day 3. Here’s What to Do.
Day 3 is a pivotal moment for almost every new family.
You’ve just been discharged. You’re exhausted. Your milk is starting to come in. And you may be noticing — for the first time — that your baby’s skin looks a little yellow.
This is one of the most common scenarios I hear from families, and the most important thing I can tell you is: don’t panic, but don’t wait either. There are concrete things you can do right now.
Feed More. Feed Often.
If jaundice is appearing or worsening, your first move is to increase feeding frequency.
Aim for every 1.5–2 hours — yes, even at night. Wake your baby if needed. A sleepy, jaundiced baby will often not wake on their own to feed, which creates a cycle: less feeding leads to less stooling, which leads to higher bilirubin, which leads to a sleepier baby. Breaking that cycle starts with you initiating feeds.
If your baby is too sleepy to latch effectively, try:
Skin-to-skin to stimulate feeding cues
Undressing baby down to a diaper during feeds to keep them alert
Stroking the jaw, tickling the feet, or switching sides frequently
Offering expressed colostrum or milk by spoon or syringe if baby won’t latch
Know the Signs That Your Milk Is Coming In
Around day 3, most women transition from colostrum to mature milk, also referred to as “milk coming in.” Recognizing this is important because it signals that your supply is ramping up, which is exactly what a jaundiced baby needs.
Signs your milk is transitioning:
Breasts feel noticeably fuller, heavier, or firmer
You may feel mild engorgement or tenderness
Baby begins swallowing more audibly during feeds
Feeding sessions feel more productive and baby seems more satisfied
You may notice leaking between feeds
If you are not noticing any of these signs by day 3–4, or if your breasts feel unchanged, reach out to a lactation consultant. Delayed transition to mature milk can contribute to the severity of jaundice.
Watch the Diapers — They Tell You a Lot
Stool color and frequency are one of your best at-home indicators of how well bilirubin is being cleared.
In the first days, your baby passes meconium — dark, sticky, greenish-black stool. As your milk comes in and intake increases, stool should begin to transition to a lighter, greenish-brown, and eventually to the seedy yellow of mature breastfed baby stool.
This transition is a good sign. It means bilirubin is moving.
By day 3–4, expect:
At least 3–4 stools per day (though more is better in a jaundiced baby)
Stool beginning to lighten in color
Increasing wet diapers — at least 4–6 per day
If stool is still meconium on day 4 or beyond, or output is low, this is a signal to call your provider and increase feeding urgency.
Make Sure a Follow-Up Appointment Is in Place
Before you leave the hospital, a follow-up appointment should be scheduled — typically within 24–48 hours of discharge, especially for babies with any jaundice noted before going home.
If you were discharged and a follow-up wasn’t clearly arranged, call your pediatrician’s office today. Don’t assume it’s scheduled. Don’t wait for them to call you.
That appointment exists to:
Recheck bilirubin levels
Assess weight and feeding
Catch any rising levels before they require more intervention
Jaundice can worsen at home before it improves. That follow-up is your safety net.
Warning Signs to Seek Help
Most families are discharged from the hospital before jaundice has peaked. Knowing what to monitor matters. Noticing a yellowish tint to the skin is your first sign to increase the amount of breastmilk your baby is receiving.
Watch for yellowing that is spreading or deepening: Jaundice typically starts at the head and moves downward. Yellowing below the belly button, or into the palms and soles, suggests higher bilirubin levels and warrants a call or urgent visit to your provider.
Count diapers: Bilirubin is cleared through the stool. Wet and dirty diapers are a good proxy for whether your baby is feeding well and moving bilirubin out. In the first week, expect increasing output day by day. If output is decreasing then seek further evaluation.
Go to the ER or Seek Immediate Care If:
Jaundice appears in the first 24 hours
Yellowing is below the belly button
Baby is extremely difficult to wake
Baby has a high-pitched cry
Baby is not feeding or output has dropped significantly
You simply feel that something is off
Trust your instincts. You know your baby.
Treatment: When Is It Needed?
Not all jaundice requires treatment beyond monitoring and feeding. When bilirubin levels rise above a certain threshold — determined by your baby’s age, weight, and risk factors — your provider may recommend:
Phototherapy (light therapy): Special blue-spectrum light helps break down bilirubin in the skin so it can be cleared more easily. This can be done in the hospital or, in some cases, at home with a bili blanket.
Increased feeding frequency: More feeding = more stooling = faster bilirubin clearance. This is often part of the plan regardless of whether phototherapy is needed.
In rare cases of very high levels, other interventions may be necessary — but this is uncommon with close monitoring.
Breastfeeding Jaundice vs. Breast Milk Jaundice — Yes, They’re Different
This comes up often, and the distinction matters.
Breastfeeding jaundice occurs in the first week of life and is related to insufficient milk intake — not breast milk itself. When a baby isn’t transferring milk effectively, they’re not stooling enough to clear bilirubin. This is the more common and more urgent of the two, and it’s directly tied to feeding frequency and milk supply. The fix is almost always more feeding, better latch, and lactation support.
Breast milk jaundice is different. It occurs after the first week — typically peaking around weeks 2–3 — and is thought to be related to substances in mature breast milk that affect bilirubin processing in the liver. It can cause bilirubin levels to remain mildly elevated for several weeks.
Breast milk jaundice is generally not harmful, does not require stopping breastfeeding, and resolves on its own. Your pediatrician will monitor levels to ensure they stay within a safe range.
If you are told your baby has “jaundice from breastfeeding” and are advised to stop nursing, ask for clarification on which type is being discussed and what the specific bilirubin level is. In most cases of breast milk jaundice, continuing to breastfeed is not only safe — it’s encouraged.
The Bottom Line
Jaundice is common. In most cases, it is manageable. But common doesn’t mean ignore it. Timing matters. Behavior matters. Feeding matters.
And if you’re navigating a jaundice diagnosis and feeling overwhelmed by the feeding piece — or by what your care team is telling you and what it means — that’s exactly why I’m here.
I offer lactation consults and healthcare navigation support to help families feel informed, not panicked. Whether you need help with feeding during treatment, or just need someone to help you understand what’s happening and what questions to ask, I’ve got you.
Because knowing what to watch for — and when to act — is everything in those early days.
— Christine Koraiban, RN BSN LC | Every Baby Feeds | Lactation Support, Education, Healthcare Navigation | North County San Diego