Newborn Jaundice — Symptoms, Causes & Treatment | MyMedicPlus

Neonatal jaundice (neonatal hyperbilirubinemia) is the yellow discolouration of skin and sclera in newborn infants caused by elevated serum total bilirubin — the result of bilirubin accumulating in skin and tissues. It is the most common condition requiring medical attention in the newborn period, affecting approximately 60% of term infants and 80% of preterm infants in the first week of life. In the majority of term newborns, jaundice is physiological — a normal adaptive response to the high fetal haemoglobin turnover after birth combined with the immature hepatic conjugation capacity (low UDP-glucuronosyltransferase activity) of the neonatal liver. Physiological jaundice appears after 24 hours of life, peaks at days 3-5 (when bilirubin reaches 8-12 mg/dL in term infants), and resolves spontaneously by day 14. However, approximately 1 in 500-750 newborns develops severe hyperbilirubinemia (bilirubin above 25 mg/dL or 430 micromol/L) carrying risk of bilirubin neurotoxicity. Bilirubin crosses the immature blood-brain barrier in neonates and deposits in the basal ganglia, brainstem nuclei, and hippocampus — causing bilirubin-induced neurological dysfunction (BIND) and the devastating long-term complication of kernicterus. Pathological jaundice — defined as appearing within the first 24 hours of life, rising faster than 0.5 mg/dL per hour, or persisting beyond 14 days (term) or 21 days (preterm) — requires urgent evaluation for underlying haemolytic disease, infection, or metabolic causes.

Physiological jaundice (the most common type — affecting 60% of term and 80% of preterm neonates) results from the normal neonatal transition: (1) high haemoglobin concentration at birth (foetal Hb is broken down as oxygen-carrying capacity needs reduce after birth, producing a large bilirubin load from haem catabolism); (2) developmentally immature UDP-glucuronosyltransferase (UGT1A1) hepatic conjugation capacity in the first week of life — limiting the liver's ability to conjugate unconjugated (indirect, lipid-soluble) bilirubin to conjugated (direct, water-soluble) bilirubin for biliary excretion. Physiological jaundice appears on day 2-3 of life (never in the first 24 hours) and resolves by day 7-10 in term infants and by day 14 in preterm. Pathological causes requiring urgent evaluation: haemolytic disease of the newborn — (a) ABO incompatibility: mother group O with infant group A or B (maternal IgG anti-A/anti-B crosses placenta); (b) Rh incompatibility: Rh-negative mother previously sensitised, producing IgG anti-D that haemolyses Rh-positive foetal red cells (now largely prevented by anti-D immunoglobulin prophylaxis in pregnancy); (c) G6PD deficiency (X-linked — common in sub-Saharan African, Mediterranean, and South Asian populations; haemolysis triggered by oxidative stress — infection, certain drugs, fava beans); (d) hereditary spherocytosis (autosomal dominant — abnormal spectrin causing fragile spherical RBCs). Sepsis, polycythaemia (venous haematocrit above 65%), hypothyroidism, and metabolic disorders (galactosaemia, Crigler-Najjar syndrome — absent UGT1A1) also cause early or severe jaundice. Breastfeeding jaundice (days 2-5): insufficient breast milk intake causing dehydration and reduced stool frequency, slowing entero-hepatic bilirubin clearance. Breast milk jaundice (distinct from breastfeeding jaundice — onset day 5-7, prolonged past 2 weeks): specific substances in breast milk (including beta-glucuronidase and fatty acids) inhibit hepatic bilirubin conjugation — diagnosis by temporary cessation of breastfeeding for 24-48 hours (bilirubin falls 30-50% confirming diagnosis) then resuming breastfeeding safely. Risk factors for significant hyperbilirubinaemia: gestational age below 38 weeks, prior sibling with neonatal jaundice requiring phototherapy, exclusive breastfeeding with weight loss, visible jaundice in first 24 hours, East Asian or Native American ethnicity, cephalhaematoma (bruising from birth trauma — additional bilirubin load from haematoma haemolysis).

Jaundice in newborns presents as progressive yellow discolouration of skin and mucous membranes, advancing in a cephalocaudal (head-to-toe) pattern as bilirubin levels rise — jaundice visible only in the face corresponds to bilirubin approximately 5-8 mg/dL; extending to the umbilicus indicates approximately 12-15 mg/dL; reaching the palms and soles indicates severe hyperbilirubinemia. Clinical assessment of skin colour under natural light (blanching the skin with a fingertip) allows bedside estimation — though this method is unreliable and should be confirmed by transcutaneous bilirubinometry (TcB) or serum total bilirubin (TSB). Yellow scleral icterus is a consistent early sign. As bilirubin levels rise, infants become increasingly sleepy (somnolent), lethargic, and feed poorly — this may self-propagate as reduced milk intake causes dehydration and further bilirubin rise. High-pitched cry is an early warning sign of bilirubin neurotoxicity. Signs of acute bilirubin encephalopathy (ABE) — a medical emergency requiring immediate exchange transfusion — include: marked lethargy and stupor, hypertonia or opisthotonus (backwards arching of the neck and trunk), high-pitched or abnormal cry, fever, poor suck, and seizures. Pale chalky-white or acholic stools combined with dark urine indicates conjugated (direct) hyperbilirubinemia from biliary obstruction (biliary atresia, choledochal cyst, neonatal hepatitis) — this is always pathological and requires urgent liver ultrasound and specialist evaluation, as untreated biliary atresia causes cirrhosis and liver failure within 2 years.

Transcutaneous bilirubinometry (TcB): a non-invasive optical device that estimates bilirubin from the skin — used as an initial screening tool for visible jaundice; values above the local threshold (varies by gestation and postnatal age) require confirmatory serum bilirubin measurement; TcB should not be used in infants receiving phototherapy or who have received exchange transfusion. Serum total bilirubin (TSB): the gold standard measurement — quantifies unconjugated plus conjugated bilirubin; the result is plotted on the Bhutani (Bilitools) gestation- and postnatal-age-specific treatment threshold graph (age in hours on X-axis, TSB on Y-axis) to determine whether phototherapy or exchange transfusion thresholds are met, and to risk-stratify into high, intermediate, or low risk zones. Direct (conjugated) bilirubin: elevated direct bilirubin above 17 mcmol/L (or above 20% of total bilirubin) indicates conjugated hyperbilirubinaemia — a different clinical entity requiring urgent separate investigation (causes: biliary atresia, Alagille syndrome, neonatal hepatitis, total parenteral nutrition, hypothyroidism, metabolic disorders); conjugated jaundice is never physiological and always pathological. Haematological investigations: blood group and Rhesus type (mother and infant); direct antiglobulin test (DAT — Coombs test: positive in ABO and Rh haemolytic disease); full blood count (anaemia from haemolysis, polycythaemia); reticulocyte count (elevated in haemolysis — above 6% in term neonates); blood film morphology (spherocytes in hereditary spherocytosis). G6PD enzyme assay: for male infants (X-linked — females heterozygous rarely have deficiency) from at-risk ethnic populations. Thyroid function: TSH for congenital hypothyroidism (screened on newborn bloodspot, but may manifest as prolonged jaundice). Urine reducing substances: if conjugated jaundice — exclude galactosaemia. Abdominal ultrasound: indicated if direct bilirubin is elevated — bile duct anomalies, liver parenchymal disease, biliary atresia (absent gallbladder, absent common bile duct — requires early Kasai procedure before 8 weeks for best outcome).

Phototherapy is the primary and most effective treatment for unconjugated hyperbilirubinemia. Blue-spectrum light (wavelength 460-490nm) converts fat-soluble unconjugated bilirubin in the skin to water-soluble photoisomers (lumirubin and configurational isomers) that can be excreted in bile and urine without hepatic conjugation — bypassing the immature neonatal conjugation pathway. Conventional phototherapy (single LED or fluorescent light source) reduces bilirubin by 1-2 mg/dL per 4-6 hours; intensive phototherapy (multiple LED banks above and below the infant, maximising irradiance above 30 microwatts/cm²/nm and maximising skin surface area exposed) achieves significantly faster bilirubin decline and is indicated for levels near exchange transfusion thresholds. The AAP 2022 revised guidelines and NICE NG98 provide age-specific bilirubin thresholds for starting phototherapy and exchange transfusion, plotted on the Bhutani nomogram. Eyes must be shielded during phototherapy. Breastfeeding should be continued throughout phototherapy — supplementation with expressed breast milk or formula is added if intake is inadequate, to ensure adequate hydration and stool frequency (which removes bilirubin excreted in bile). Exchange transfusion — replacing approximately 85 mL/kg of the infant's blood with compatible donor blood through a double-volume exchange — rapidly reduces bilirubin by 50-60% and is life-saving in severe hyperbilirubinemia with acute bilirubin encephalopathy or when intensive phototherapy fails to lower bilirubin below the exchange threshold within 4-6 hours. Intravenous immunoglobulin (IVIG) 0.5-1g/kg is effective in ABO and Rh haemolytic disease — reducing haemolysis and the need for exchange transfusion. Tin-mesoporphyrin (stannsoporfin) inhibits haem oxygenase to reduce bilirubin production, but is not yet widely available.

Kernicterus (chronic bilirubin encephalopathy) is the most feared and preventable complication of neonatal hyperbilirubinemia. Unconjugated bilirubin crosses the immature neonatal blood-brain barrier and deposits in the basal ganglia (especially the globus pallidus), subthalamic nuclei, hippocampus, brainstem nuclei (cochlear, oculomotor), and cerebellum — causing irreversible neuronal death. The classic kernicterus tetrad consists of: athetoid (dyskinetic) cerebral palsy with involuntary movements; sensorineural hearing loss (auditory neuropathy — often severe, causing deafness); oculomotor paresis (upward gaze palsy — Parinaud's phenomenon); and enamel dysplasia of the primary dentition. Intellectual disability may occur but is not universal. Kernicterus is entirely preventable with timely identification and treatment of severe hyperbilirubinemia. In sick, very preterm, or septic infants, blood-brain barrier immaturity and reduced albumin binding allow bilirubin neurotoxicity at much lower total bilirubin levels than in healthy term newborns — hence lower phototherapy thresholds in preterm and sick neonates. Bilirubin-induced neurological dysfunction (BIND) scoring assesses the degree of acute encephalopathy. Prolonged phototherapy may cause bronze baby syndrome (harmless gray-brown discoloration from porphyrin metabolites) and reversible DNA damage — phototherapy should be discontinued as soon as bilirubin falls below treatment thresholds.

Universal pre-discharge jaundice screening with transcutaneous bilirubinometry (TcB) or serum bilirubin at 24-48 hours of age, plotted on the Bhutani hour-specific nomogram, identifies newborns at high or intermediate risk for subsequent severe hyperbilirubinemia — enabling planned early follow-up. Risk factor assessment at discharge identifies infants requiring follow-up at 2-3 days: exclusive breastfeeding, gestational age 35-37 weeks, previous sibling with jaundice requiring phototherapy, blood group mismatch, East Asian or Native American ethnicity, and visible jaundice at discharge. Rhesus (Rh) prevention: all Rh-negative mothers receive anti-D immunoglobulin (anti-D prophylaxis — RhIG) at 28 weeks gestation (antenatal), after any sensitising events (amniocentesis, antepartum haemorrhage, trauma), and within 72 hours of delivering an Rh-positive infant — preventing maternal Rh sensitisation and eliminating Rh haemolytic disease of the newborn in subsequent pregnancies. ABO incompatibility cannot currently be prevented but can be detected by a positive direct antiglobulin test (DAT) at birth, prompting increased bilirubin surveillance. Breastfeeding promotion and support: ensuring 8-12 breastfeeds per day in the first 72 hours, assessing latch and milk transfer, and supplementing with expressed breast milk or formula when intake is inadequate — prevents breastfeeding jaundice from dehydration. Parental education before discharge on recognising worsening jaundice (spreading to trunk and extremities), signs of concern (poor feeding, excessive sleepiness), and when to seek urgent review is a mandatory standard of neonatal discharge care.

Seek emergency care immediately for: jaundice appearing within the first 24 hours of life — this is always pathological and requires urgent blood tests and investigation for haemolytic disease, G6PD deficiency, or infection; rapidly deepening jaundice spreading to the trunk, abdomen, and palms within 24-48 hours; and any signs of acute bilirubin encephalopathy — a very drowsy or unrousable baby, poor feeding with high-pitched cry, arching of the back (opisthotonus), seizures, or fever — these indicate emergency exchange transfusion. Take your baby to a paediatrician or A&E urgently (within hours) for: jaundice persisting beyond 14 days in a term infant (or 21 days in a preterm infant) — requires investigation for pathological causes including biliary atresia; pale or chalky-white stools with dark urine suggesting conjugated (direct) jaundice and biliary obstruction (biliary atresia must be excluded urgently — Kasai surgery before 60 days dramatically improves outcomes); and any jaundiced newborn who is not feeding well, is excessively sleepy, or has lost more than 10% of birth weight. All parents should be educated before hospital discharge on identifying worsening jaundice by skin colour progression and ensuring adequate feeding.