Most newborn jaundice is treated with phototherapy, a light-based treatment that breaks down the yellow pigment (bilirubin) in your baby’s skin so their body can eliminate it. About 60% of full-term newborns develop some degree of jaundice in their first week, and the vast majority respond well to phototherapy alone. In more severe cases, additional interventions like immune globulin infusions or blood exchange transfusions may be needed, but these are uncommon.
Why Bilirubin Builds Up in Newborns
Bilirubin is a byproduct of red blood cell breakdown. Newborns produce more of it than adults because they’re born with extra red blood cells they no longer need outside the womb, and their livers are still maturing. A healthy liver filters bilirubin out of the blood and sends it into the intestines, where it leaves the body through stool. When this process can’t keep up, bilirubin accumulates and turns the skin and whites of the eyes yellow.
Normal bilirubin levels sit between 0.1 and 1.2 mg/dL. Visible yellowing typically appears once levels reach about 2.0 mg/dL. At 25 mg/dL or higher, there is serious risk of a condition called kernicterus, where bilirubin crosses into the brain and causes permanent damage. Treatment exists specifically to prevent bilirubin from ever reaching that danger zone.
How Bilirubin Levels Are Measured
Hospitals typically start with a skin-based meter that estimates bilirubin by shining light through your baby’s skin. These devices are painless and give results in seconds. Cochrane research shows their sensitivity for detecting high bilirubin ranges from 74% to 100%, making them reliable screening tools. However, accuracy varies depending on the device, your baby’s age, and skin color. If the skin reading comes back elevated, a small blood draw confirms the exact level. That blood test, called total serum bilirubin (TSB), is the gold standard that guides all treatment decisions.
During phototherapy, bilirubin levels are rechecked every 4 to 6 hours initially, then at longer intervals once levels start dropping steadily.
Phototherapy: The First-Line Treatment
Phototherapy uses blue-spectrum light to change the structure of bilirubin molecules sitting in tiny blood vessels just under the skin. The altered bilirubin becomes water-soluble, meaning your baby’s body can flush it out through urine and stool without the liver needing to process it first.
Your baby will lie in a bassinet or warmer wearing only a diaper, with soft eye shields to protect their retinas. Some hospitals use fiber-optic blankets or pads placed directly against the skin, which can be wrapped around the baby. In intensive phototherapy, multiple light sources surround the baby to maximize skin exposure. The American Academy of Pediatrics sets specific thresholds for starting phototherapy based on your baby’s gestational age, age in hours, and whether they have risk factors like blood type incompatibility or premature birth.
Most babies need phototherapy for one to two days, though the exact duration depends on how high bilirubin was at the start and how quickly it drops. Phototherapy is paused briefly for feeding and diaper changes. You can hold and breastfeed your baby during these breaks. Once bilirubin falls well below the treatment threshold, the lights are turned off and a follow-up blood test is done 6 to 24 hours later to check for rebound, a rise in bilirubin after treatment stops.
Checking for Rebound After Treatment
Babies born before 37 weeks, those with blood type incompatibility causing ongoing red blood cell destruction, and those who aren’t feeding well are at higher risk for rebound. These babies are typically rechecked within 12 hours of stopping phototherapy. Lower-risk babies, particularly those who started phototherapy after 48 hours of age with no signs of hemolysis, may be discharged with a pediatrician follow-up within 24 hours for a repeat bilirubin check.
When Phototherapy Isn’t Enough
If bilirubin keeps rising despite intensive phototherapy, or climbs to within 2 mg/dL of the exchange transfusion threshold, the care team escalates treatment. There are two main options beyond phototherapy.
Intravenous Immune Globulin (IVIG)
When jaundice is caused by a mismatch between the mother’s and baby’s blood types, the mother’s antibodies attack the baby’s red blood cells, releasing bilirubin faster than the body can clear it. IVIG is a concentrated infusion of antibodies that blocks this destruction. It’s given when bilirubin is rising rapidly (more than 0.5 mg/dL per hour) despite intensive phototherapy, and it can eliminate the need for a blood exchange transfusion. The infusion takes about two hours and can be repeated every 12 hours if needed. About one in six babies treated with IVIG avoids exchange transfusion because of it.
Exchange Transfusion
This is the most aggressive treatment, reserved for dangerously high bilirubin that isn’t responding to other interventions. Small amounts of your baby’s blood are withdrawn and replaced with donor blood in a carefully controlled cycle. This directly removes bilirubin from the bloodstream and replaces the antibody-coated red blood cells being destroyed. The procedure takes place in a neonatal intensive care unit with continuous monitoring of heart rate, temperature, and blood chemistry. It’s effective but carries risks, so it’s used only when the alternative, potential brain damage, is worse.
Why Feeding Matters So Much
Bilirubin leaves the body through stool, so the more your baby poops, the faster levels drop. Frequent feeding is one of the most important things you can do. Breastfed babies should nurse 8 to 12 times in 24 hours, roughly every 2.5 to 3 hours. This serves a dual purpose: it moves bilirubin out through the gut and stimulates your milk supply during the critical early days.
If breastfeeding alone isn’t providing enough volume, your pediatrician may suggest small supplemental formula feedings of 10 to 15 mL right after nursing. These small top-ups help increase stool output without undermining breastfeeding, since the baby continues to nurse at full frequency. Formula-fed infants tend to take in higher volumes earlier (around 150 mL per day in the first days), which is one reason formula-fed babies develop significant jaundice less often.
Breastfeeding should not be stopped because of jaundice. The early, frequent nursing that prevents dehydration and encourages stool passage is itself a form of treatment.
What About Sunlight?
You may hear that placing your baby near a sunny window helps with jaundice. Direct sunlight does lower bilirubin levels, and the AAP acknowledges this. However, it is not recommended as a treatment because there’s no practical way to control the dose. Newborn skin burns easily, and even brief unprotected sun exposure carries risks of overheating, sunburn, and dehydration. Filtered sunlight has shown promise in research settings in low-resource countries where phototherapy equipment isn’t available, but in settings where standard phototherapy is accessible, sunlight is not a substitute.
What to Expect After Discharge
Most babies go home within a day or two of completing phototherapy. Your pediatrician will schedule a follow-up visit within 24 to 48 hours to recheck bilirubin, depending on your baby’s risk profile. At home, keep feeding frequently and watch for the yellow tint spreading or deepening, poor feeding, excessive sleepiness, or a high-pitched cry. Stool color matters too: yellow, seedy stools in breastfed babies signal that bilirubin is clearing normally. Pale or white stools can indicate a liver problem unrelated to typical newborn jaundice and need prompt evaluation.
For the large majority of newborns, jaundice resolves completely within one to two weeks with no lasting effects. Premature babies and those with underlying hemolytic conditions may need closer monitoring over a longer window, but even in these cases, outcomes are excellent when bilirubin is caught and managed early.