Newborn jaundice, a yellowish discoloration of the skin and eyes, is common in infants during their first few days of life. This yellowing occurs due to excess bilirubin in the blood, a yellow pigment produced when red blood cells break down. While bilirubin is normally processed and excreted by the liver, a newborn’s immature liver may not remove it quickly enough, leading to accumulation. This is why jaundice is observed in approximately 60% of full-term babies and 80% of premature infants within their first week.
Understanding Physiological Jaundice
Physiological jaundice is the most frequent type of jaundice in newborns and is a normal, temporary condition. It appears after the first 24 hours of life, often between the second and fourth day following birth. The underlying reason is the newborn’s still-developing liver, which is not yet fully efficient at processing bilirubin.
Newborns also produce more bilirubin than adults because they have a higher concentration of red blood cells. These cells have a shorter lifespan and break down more rapidly in the initial days after birth. This increased bilirubin production, combined with the liver’s limited capacity to process and excrete it, leads to a temporary buildup. Physiological jaundice usually peaks around 3 to 7 days after birth and resolves within one to two weeks as the baby’s liver matures and becomes more effective at clearing bilirubin.
Understanding Pathological Jaundice
Pathological jaundice, in contrast, is less common but indicates an underlying medical issue that interferes with bilirubin processing. This form of jaundice often appears within the first 24 hours of life, signaling a potentially rapid escalation of bilirubin levels. Its early onset and potential for high bilirubin concentrations necessitate prompt medical attention to prevent complications.
Various underlying conditions can cause pathological jaundice. These include blood group incompatibilities, such as Rh or ABO incompatibility, where the mother’s antibodies attack the baby’s red blood cells, leading to increased bilirubin production. Infections, certain genetic conditions like Gilbert’s syndrome or Crigler-Najjar syndrome, and liver disorders can also impair the liver’s ability to process bilirubin. Conditions like an underactive thyroid gland, biliary atresia (a blockage in the bile ducts), or metabolic disorders can also contribute. If left untreated, excessively high bilirubin levels can lead to severe neurological complications, including kernicterus, a rare but serious type of brain damage.
Key Differences and When to Be Concerned
Distinguishing between physiological and pathological jaundice is important for appropriate medical care. The timing of onset is a primary indicator; physiological jaundice typically appears after 24 hours, while pathological jaundice often manifests within the first 24 hours of birth. Bilirubin levels in physiological jaundice tend to be lower and peak later, generally not exceeding 12 mg/dL in full-term infants. In contrast, pathological jaundice levels can be significantly higher and rise more rapidly.
The duration also differs: physiological jaundice usually subsides within one to two weeks, whereas pathological jaundice may be prolonged or worsen over time, lasting beyond one week in full-term infants or two weeks in premature babies. Physiological jaundice generally presents without other concerning symptoms, with the baby appearing otherwise healthy. Pathological jaundice may be accompanied by additional signs, such as poor feeding, excessive lethargy, irritability, a high-pitched cry, dark urine, or pale stools. These associated symptoms, along with causes like blood incompatibilities or infections, differentiate pathological jaundice.
Specific warning signs that warrant immediate medical attention include:
Jaundice appearing within the first 24 hours after birth.
A rapid increase in the yellowness of the skin, or if the yellowing spreads to the abdomen, arms, or legs.
A baby who seems listless, unusually drowsy, difficult to awaken, or feeds poorly.
Dark urine and pale or clay-colored stools.
Diagnosis and Management Approaches
The diagnosis of jaundice typically begins with a physical examination, where a healthcare provider assesses the yellowing of the baby’s skin and eyes. To confirm the diagnosis and determine severity, bilirubin levels are measured through a blood test or a transcutaneous bilirubinometer, a device that measures bilirubin by shining light through the skin. These measurements help guide the appropriate course of action.
For physiological jaundice, management often involves close monitoring of bilirubin levels and encouraging frequent feedings, as this helps the baby excrete bilirubin through bowel movements. If bilirubin levels are moderately elevated, phototherapy may be used. This treatment involves placing the baby under special blue-green lights, which change bilirubin molecules into a form that can be more easily excreted in urine and stool.
For pathological jaundice, more intensive treatments are often necessary, including phototherapy. In severe cases, an exchange transfusion replaces a baby’s blood with donor blood to rapidly lower bilirubin levels. Addressing the underlying cause, such as treating an infection or managing a specific medical condition, is also a primary focus. Consistent medical follow-up and adherence to professional advice are important for all newborns with jaundice.