Newborn jaundice and light therapy

Newborn jaundice and light therapy: What parents need to know

Many newborns develop jaundice within the first few days of life. For parents, seeing a yellow tint in their baby's skin or eyes can be concerning. Jaundice is common and often harmless, but some babies require treatment to prevent complications. Understanding what jaundice is and how it's managed can help parents feel prepared and reassured.

Understanding newborn jaundice

Jaundice occurs when a baby has elevated levels of bilirubin, a yellow pigment produced as the body breaks down red blood cells. Newborns have immature livers that may not remove bilirubin efficiently, causing it to build up in the bloodstream and settle in the skin and eyes.

The condition affects 50%–80% of newborns in the United States. While most full-term babies experience mild jaundice that resolves on its own, higher levels of bilirubin can be dangerous. If untreated, severe jaundice in babies can lead to permanent brain damage, so early recognition and monitoring are essential.

Other symptoms of jaundice in infants include difficulty waking, seeming listless or sick, not gaining weight, feeding poorly and making high-pitched cries.

When treatment is needed

Not all cases of jaundice require medical intervention. Babies born between 35 weeks and full term frequently improve without treatment. However, if a baby's bilirubin levels rise too quickly or reach a level that is considered unsafe, intervention is necessary to prevent complications.

Clinicians determine treatment needs based on bilirubin levels, the baby's age, gestational age, feeding patterns and other risk factors.

How light therapy works

Phototherapy, or light therapy, is one of the most common treatments for newborn jaundice.

Phototherapy uses a specific range of blue-green visible light. When this light reaches the baby's skin, it changes bilirubin into a water-soluble form that the body can eliminate through stool and urine. The treatment is safe, effective and noninvasive.

During therapy, babies typically wear only a diaper and protective eye patches. Maximizing skin exposure helps improve treatment efficiency.

Ensuring safe and effective treatment

In 2024, the American Academy of Pediatrics updated its recommendations on phototherapy to specify the most effective light intensity. Increasing the brightness beyond these guidelines does not improve outcomes and may decrease safety.

In the November 2025 issue of Hospital Pediatrics, new insights were published on how factors such as covers or swaddles can influence phototherapy effectiveness in newborns.

Short-term side effects can include skin rashes, dehydration and overheating. The most important safety measure is protecting the baby's eyes, as direct exposure to the light could harm their retinas.

Clinicians follow clear, individualized guidelines for when to begin and discontinue phototherapy.

Why sunlight isn't a substitute

Sunlight contains ultraviolet and infrared radiation. These can cause sunburn, overheating and dehydration. For this reason, sunlight is not recommended as a treatment for jaundice.

Phototherapy provides a safe and controlled exposure without these risks.

Supporting your baby at home

The best way for you to prevent your baby from developing jaundice after birth is to make sure the baby is getting fed on a regular schedule. Infants typically need 8–12 feedings each day in the first several days of life.

Parents should monitor their newborn for changes in skin color, feeding patterns, alertness and weight. If you have concerns, it is important to contact your baby's healthcare provider promptly.

Promoting healthy beginnings

Jaundice is a common part of newborn life, and most cases resolve with simple monitoring and supportive care. When treatment is needed, phototherapy offers a gentle and reliable way to prevent the serious complications of high bilirubin. With early recognition and proper care, parents can feel confident that their baby is off to a healthy start.

Dennis Costakos, M.D., is a neonatal physician for the Mayo Clinic Health System in La Crosse, Wisconsin.