Michael S. Porter
Eric C. Nordby
When a newborn develops severe jaundice that goes untreated, the resulting buildup of bilirubin can cause a rare but serious form of brain damage called kernicterus. While this condition has become uncommon in the United States due to better screening and treatment, it remains one of the most devastating preventable outcomes of the newborn period. Understanding kernicterus helps families recognize warning signs early and ensures that babies receive the prompt care they need.
This page explains what kernicterus is, how it develops, what symptoms to watch for, and how medical teams work to prevent and manage this condition.
What Is Kernicterus?
Kernicterus is a type of brain injury caused by dangerously high levels of bilirubin in a newborn’s bloodstream. Bilirubin is a yellow pigment that forms naturally when red blood cells break down. In healthy newborns, the liver processes and removes bilirubin from the body. But when bilirubin levels rise too high and remain elevated, this substance can cross into the brain and damage critical areas that control movement, hearing, vision, and development.
Medical professionals sometimes use the term bilirubin-induced neurologic dysfunction, or BIND, to describe the spectrum of injury that can occur. Kernicterus represents the most severe form of this damage.
Most newborns experience some degree of jaundice in their first days of life. This is normal and typically harmless. Kernicterus only occurs when jaundice becomes severe and is not treated in time. With proper monitoring and early intervention, kernicterus is almost entirely preventable.
How Kernicterus Develops
Newborns are naturally at higher risk for elevated bilirubin because their livers are still maturing and learning to process this substance efficiently. At the same time, babies are born with extra red blood cells left over from fetal development, and as these cells break down in the first few days of life, bilirubin levels rise.
In most cases, the baby’s liver catches up within a week or two, and bilirubin levels return to normal without any intervention. But certain factors can push bilirubin to dangerous levels, including:
Prematurity
Babies born before 37 weeks have less mature livers and are more vulnerable to rising bilirubin levels.
Blood Type Incompatibility
When a mother and baby have incompatible blood types, such as Rh or ABO incompatibility, the baby’s red blood cells may break down more quickly than normal, leading to a surge in bilirubin.
G6PD Deficiency
Glucose-6-phosphate dehydrogenase deficiency is an inherited condition that makes red blood cells more fragile. New York State now requires universal screening for G6PD deficiency in all newborns, providing an added safety measure against severe jaundice.
Bruising or Birth Trauma
Significant bruising from a difficult delivery can lead to increased red blood cell breakdown and higher bilirubin levels.
Infections and Metabolic Conditions
Sepsis, dehydration, and rare genetic disorders like Crigler-Najjar syndrome can interfere with bilirubin processing.
Feeding Difficulties
Babies who are not feeding well in the first days of life may become dehydrated, which can concentrate bilirubin in the bloodstream.
Research also shows that Black infants in the United States are disproportionately affected by severe jaundice and kernicterus, likely due to a combination of genetic factors and disparities in healthcare access and follow-up care.
Recognizing the Warning Signs
Kernicterus does not happen suddenly. It develops over time as bilirubin levels climb and begin affecting the brain. Parents and caregivers should be aware of the early warning signs of severe jaundice, which include:
- Yellow or orange discoloration of the skin and the whites of the eyes, especially on the face and chest
- Marked sleepiness or difficulty waking the baby for feedings
- Weak or poor sucking during breastfeeding or bottle feeding
- Decreased wet diapers or signs of dehydration
- Increased fussiness or irritability
If jaundice is not treated and bilirubin continues to rise, a baby may develop more serious symptoms that suggest brain involvement. These can appear in stages:
Early Phase
The baby becomes very floppy and lethargic, with poor muscle tone. Feeding becomes difficult, and the baby may seem unresponsive or hard to rouse.
Intermediate Phase
The baby may develop muscle stiffness, arching of the back and neck (a condition called opisthotonos), a high-pitched or shrill cry, and fever. These signs indicate that bilirubin is actively damaging the brain.
Chronic Phase
If kernicterus has occurred, the baby may initially seem to improve, but long-term effects become apparent over weeks and months. These can include movement disorders similar to cerebral palsy, hearing loss, difficulty with upward gaze, dental staining, and intellectual or developmental delays.
Any baby showing signs of severe jaundice or unusual behavior should be evaluated by a healthcare provider immediately. Early action is critical in preventing permanent injury.
How Kernicterus Is Diagnosed
Diagnosis begins with careful monitoring of bilirubin levels in the newborn period. Most hospitals use a handheld light meter that measures bilirubin through the skin, a test called transcutaneous bilirubinometry. If the reading is elevated, a blood test confirms the exact bilirubin level.
The American Academy of Pediatrics recommends that all newborns be screened for jaundice before leaving the hospital and again at three to five days of age, when bilirubin typically peaks. Babies at higher risk may need more frequent monitoring.
If a baby shows neurological symptoms, doctors will perform a thorough physical and neurological exam. In cases where kernicterus is suspected, an MRI of the brain can help confirm the diagnosis by revealing characteristic patterns of injury in areas like the globus pallidus and subthalamic nuclei.
Medical teams also work to identify the underlying cause of the elevated bilirubin, which may involve testing for blood type incompatibility, G6PD deficiency, infections, or metabolic disorders.
Treatment and Prevention
Kernicterus is considered almost entirely preventable with appropriate medical care. The key to prevention is catching rising bilirubin levels early and treating them before they reach dangerous levels.
Phototherapy
The most common and effective treatment for elevated bilirubin is phototherapy, or light therapy. The baby is placed under special blue lights that help break down bilirubin in the skin so it can be excreted more easily. Phototherapy is safe, painless, and highly effective when started promptly.
Exchange Transfusion
In severe cases where bilirubin levels are extremely high (usually above 25 to 30 mg/dL) or rising rapidly despite phototherapy, doctors may perform an exchange transfusion. This procedure involves slowly removing small amounts of the baby’s blood and replacing it with donor blood to quickly lower bilirubin levels. While more intensive, exchange transfusion can be lifesaving in critical situations.
Supportive Care
Ensuring that the baby is well-hydrated and feeding effectively also helps the body process and eliminate bilirubin. Medical teams may provide feeding support, monitor fluid intake, and address any underlying conditions contributing to jaundice.
Current guidelines from the American Academy of Pediatrics and New York State health authorities emphasize the importance of universal screening, timely follow-up, and culturally responsive care to reduce disparities in outcomes.
Living With Kernicterus
For children who have experienced kernicterus, the effects can be lifelong. The severity of disability varies depending on how much brain damage occurred and which areas were affected. Some children may have mild symptoms, while others face significant challenges with movement, communication, hearing, and learning.
Long-term care typically involves a team of specialists, including:
- Neurologists to monitor brain function and development
- Physical and occupational therapists to address movement and motor skills
- Speech and language therapists to support communication
- Audiologists to manage hearing loss
- Nutritionists and feeding specialists if eating difficulties are present
Early intervention programs, available through state health departments including New York, provide crucial support during the first years of life. These programs connect families with therapies and services designed to help children reach their fullest potential.
Major medical centers throughout New York, including Mount Sinai, NYU Langone, and Columbia Presbyterian, offer specialized care for children affected by kernicterus. Families can also access patient support organizations that provide resources, education, and connections to other families navigating similar experiences.
Incidence and Current Trends
Thanks to improved screening and treatment protocols, kernicterus has become rare in developed countries. Current estimates suggest that kernicterus occurs in approximately one to two out of every 100,000 live births in the United States. Yet avoidable cases still occur, often due to missed follow-up appointments, delayed recognition of symptoms, or gaps in communication between families and healthcare providers.
Recent research continues to explore better ways to predict which babies are at highest risk, improve outcomes for those affected, and address persistent disparities in care. There is growing advocacy for health equity, better parental education about jaundice, and stronger systems to ensure that no baby is lost to follow-up during the critical first weeks of life.
Finding Support and Information
Families affected by kernicterus often feel overwhelmed by the medical complexity and emotional weight of the diagnosis. Knowing where to turn for accurate information and support can make a meaningful difference.
NYBirthInjury.com exists to provide trusted, evidence-based information and to connect families with qualified medical and support resources. Whether you are trying to understand a diagnosis, seeking clarity about your baby’s care, or looking for next steps, having reliable information is the foundation for making informed decisions.
Kernicterus is a serious condition, but with awareness, vigilant monitoring, and prompt treatment, the vast majority of cases can be prevented. For families already navigating this journey, comprehensive care and early intervention offer hope and meaningful opportunities for progress.