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Clinical manifestations of unconjugated hyperbilirubinemia in term and late preterm infants

Ronald J Wong, BA
Vinod K Bhutani, MD, FAAP
Section Editor
Steven A Abrams, MD
Deputy Editor
Melanie S Kim, MD


Almost all newborn infants develop a total serum or plasma bilirubin (TB) value greater than 1 mg/dL (17.1 micromol/L), which is the upper limit of normal for adults. As TB increases, it can cause neonatal jaundice, the yellowish discoloration of the skin and/or conjunctiva caused by bilirubin deposition in half of all newborn infants. Neonates with severe hyperbilirubinemia (defined as a TB >25 mg/dL [428 micromol/L]) are at risk for bilirubin-induced neurologic dysfunction (BIND), which occurs when bilirubin crosses the blood-brain barrier, binds to brain tissue, and then causes neurotoxicity.

The clinical manifestations of and risk factors for severe neonatal unconjugated hyperbilirubinemia in term and late preterm infants are reviewed here. The pathogenesis, etiology, evaluation, prevention, and treatment are discussed separately. (See "Pathogenesis and etiology of unconjugated hyperbilirubinemia in the newborn" and "Evaluation of unconjugated hyperbilirubinemia in term and late preterm infants" and "Treatment of unconjugated hyperbilirubinemia in term and late preterm infants".)


Neonatal hyperbilirubinemia in infants ≥35 weeks gestational age (GA) is defined as total serum or plasma bilirubin (TB) >95th percentile on the hour-specific Bhutani nomogram (figure 1) [1].

Severe neonatal hyperbilirubinemia is defined as a TB >30 mg/dL (513 micromol/L). It is associated with an increased risk for bilirubin-induced neurologic dysfunction (BIND), which occurs when bilirubin crosses the blood-brain barrier, binds to brain tissue, and causes neurotoxicity. (See 'Neurologic dysfunction and moderate hyperbilirubinemia' below.)

Acute bilirubin encephalopathy (ABE) is used to describe the acute manifestations of BIND. (See 'Acute bilirubin encephalopathy' below.)

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Literature review current through: Nov 2017. | This topic last updated: Oct 11, 2017.
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