MBBS Year
1st Year
Subject
What Is Usually Asked
Bilirubin metabolism, conjugation, Crigler-Najjar and Gilbert syndromes
ReferenceAll Years (1st-Final)All UniversitiesNeonatal Jaundice
Neonatal Jaundice: Notes, PPT and PYQs for MBBS
Neonatal jaundice is yellow discolouration of a newborn's skin and eyes caused by raised serum bilirubin. It is very common and usually physiological, but pathological jaundice can lead to bilirubin encephalopathy and kernicterus if missed. It is a core Final Year Paediatrics topic, with links to Physiology, Biochemistry and Obstetrics.
SME-reviewed. Updated 2026.
Open in GeckoMed for PPT slides and notes.Quick Summary: What You Need to Know for University Exams
- Jaundice becomes visible in newborns at a serum bilirubin of about 5 mg/dL.
- Physiological jaundice appears after 24 hours, peaks around days 3 to 5 in term babies and settles within about 2 weeks.
- Jaundice within the first 24 hours is always pathological.
- Important causes: Rh and ABO haemolytic disease, G6PD deficiency, sepsis, and conjugated causes such as biliary atresia.
- Phototherapy is the main treatment; exchange transfusion is used for severe or rapidly rising bilirubin.
- Untreated severe unconjugated hyperbilirubinaemia can cause kernicterus.
- Pale stools with dark urine point to conjugated jaundice and need urgent evaluation for biliary atresia.
Neonatal Jaundice Across MBBS Subjects
| MBBS Year | Subject | What Is Usually Asked |
|---|---|---|
| 1st Year | Biochemistry | Bilirubin metabolism, conjugation, Crigler-Najjar and Gilbert syndromes |
| 1st Year | Physiology | Fetal and neonatal red cells |
| 2nd Year | Pathology | Haemolytic disease of the newborn |
| Final Year | Paediatrics | Physiological versus pathological jaundice, evaluation, phototherapy, exchange transfusion |
| Final Year | Obstetrics and Gynaecology | Rh isoimmunisation and anti-D prophylaxis |
MBBS Year
1st Year
Subject
What Is Usually Asked
Fetal and neonatal red cells
MBBS Year
2nd Year
Subject
What Is Usually Asked
Haemolytic disease of the newborn
MBBS Year
Final Year
Subject
What Is Usually Asked
Physiological versus pathological jaundice, evaluation, phototherapy, exchange transfusion
MBBS Year
Final Year
Subject
What Is Usually Asked
Rh isoimmunisation and anti-D prophylaxis
Definition and Classification
Definition: Neonatal jaundice is yellowish discolouration of the skin and sclera in a newborn due to raised serum bilirubin (hyperbilirubinaemia).
Physiological Versus Pathological Jaundice
| Feature | Physiological | Pathological |
|---|---|---|
| Onset | After 24 hours | Within the first 24 hours, or any time with worrying features |
| Peak (term baby) | Around days 3 to 5 | Variable |
| Duration | Resolves within about 2 weeks in term babies (longer in preterm babies) | Persists beyond 2 weeks in term or 3 weeks in preterm babies |
| Rate of rise | Slow | Rapid (more than about 5 mg/dL per day) |
| Bilirubin level | Below phototherapy thresholds | Above age-specific phototherapy thresholds |
| Conjugated bilirubin | Not raised | May be raised (any significant rise is pathological) |
| Baby's condition | Well | May be unwell, lethargic or feeding poorly |
Feature
Onset
Physiological
After 24 hours
Pathological
Within the first 24 hours, or any time with worrying features
Feature
Peak (term baby)
Physiological
Around days 3 to 5
Pathological
Variable
Feature
Duration
Physiological
Resolves within about 2 weeks in term babies (longer in preterm babies)
Pathological
Persists beyond 2 weeks in term or 3 weeks in preterm babies
Feature
Rate of rise
Physiological
Slow
Pathological
Rapid (more than about 5 mg/dL per day)
Feature
Bilirubin level
Physiological
Below phototherapy thresholds
Pathological
Above age-specific phototherapy thresholds
Feature
Conjugated bilirubin
Physiological
Not raised
Pathological
May be raised (any significant rise is pathological)
Feature
Baby's condition
Physiological
Well
Pathological
May be unwell, lethargic or feeding poorly
Aetiology (Causes)
Unconjugated Hyperbilirubinaemia
| Category | Causes |
|---|---|
| Physiological | Normal newborn adaptation |
| Haemolytic | Rh isoimmunisation, ABO incompatibility (typically mother group O, baby group A or B), G6PD deficiency, hereditary spherocytosis |
| Increased red cell breakdown | Cephalhaematoma, bruising, polycythaemia |
| Infection | Neonatal sepsis |
| Feeding-related | Breastfeeding (suboptimal intake) jaundice in the first week; breast milk jaundice later, peaking in the second or third week |
| Endocrine and genetic | Hypothyroidism (prolonged jaundice), Crigler-Najjar syndrome, Gilbert syndrome |
| Others | Intestinal obstruction, maternal diabetes, prematurity |
Category
Physiological
Causes
Normal newborn adaptation
Category
Haemolytic
Causes
Rh isoimmunisation, ABO incompatibility (typically mother group O, baby group A or B), G6PD deficiency, hereditary spherocytosis
Category
Increased red cell breakdown
Causes
Cephalhaematoma, bruising, polycythaemia
Category
Infection
Causes
Neonatal sepsis
Category
Feeding-related
Causes
Breastfeeding (suboptimal intake) jaundice in the first week; breast milk jaundice later, peaking in the second or third week
Category
Endocrine and genetic
Causes
Hypothyroidism (prolonged jaundice), Crigler-Najjar syndrome, Gilbert syndrome
Category
Others
Causes
Intestinal obstruction, maternal diabetes, prematurity
Conjugated Hyperbilirubinaemia (Always Pathological)
- Biliary atresia
- Neonatal hepatitis
- Congenital infections (TORCH)
- Choledochal cyst
- Metabolic disorders such as galactosaemia
- Sepsis and prolonged parenteral nutrition
Pathophysiology
Why Newborns Develop Jaundice (Physiological Mechanisms)
- Increased bilirubin production: Newborns have a high red cell mass, and fetal red cells have a shorter lifespan
- Reduced uptake: Lower levels of the liver binding protein (ligandin)
- Reduced conjugation: Immature activity of the liver enzyme UDP-glucuronyl transferase
- Increased enterohepatic circulation: Gut enzymes deconjugate bilirubin, which is then reabsorbed
Bilirubin Encephalopathy
- Very high unconjugated bilirubin exceeds the binding capacity of albumin
- Free unconjugated bilirubin, which is lipid-soluble, crosses the blood-brain barrier
- It deposits in the basal ganglia (especially the globus pallidus), hippocampus, brainstem nuclei and cerebellum
- This causes neuronal injury (bilirubin encephalopathy) and, if permanent, kernicterus
Risk factors for brain injury: prematurity, haemolysis, sepsis, acidosis, hypoalbuminaemia and drugs that displace bilirubin from albumin.
(Examiner may ask you to draw the bilirubin metabolism pathway.)
Clinical Features
- Yellow skin and sclera, progressing from the head downwards (cephalocaudal progression)
- Dark urine and pale stools in conjugated jaundice
- Pallor, hepatosplenomegaly or hydrops in haemolytic disease
- Lethargy, poor feeding or temperature instability in sepsis
Kramer's Rule (Clinical Estimate)
| Zone | Area | Approximate Bilirubin (mg/dL) |
|---|---|---|
| 1 | Head and neck | About 4 to 8 |
| 2 | Upper trunk to umbilicus | About 5 to 12 |
| 3 | Lower trunk and thighs | About 8 to 16 |
| 4 | Arms and legs below knees | About 11 to 18 |
| 5 | Palms and soles | Above 15 |
Zone
1
Area
Head and neck
Approximate Bilirubin (mg/dL)
About 4 to 8
Zone
2
Area
Upper trunk to umbilicus
Approximate Bilirubin (mg/dL)
About 5 to 12
Zone
3
Area
Lower trunk and thighs
Approximate Bilirubin (mg/dL)
About 8 to 16
Zone
4
Area
Arms and legs below knees
Approximate Bilirubin (mg/dL)
About 11 to 18
Zone
5
Area
Palms and soles
Approximate Bilirubin (mg/dL)
Above 15
Kramer's rule is only a rough guide. Always confirm with transcutaneous or serum bilirubin measurement.
Acute Bilirubin Encephalopathy
| Phase | Features |
|---|---|
| Early | Lethargy, hypotonia, poor suck |
| Intermediate | Irritability, high-pitched cry, hypertonia, arching of the neck (retrocollis) and back (opisthotonus), fever |
| Advanced | Deep stupor or coma, seizures, apnoea |
Phase
Early
Features
Lethargy, hypotonia, poor suck
Phase
Intermediate
Features
Irritability, high-pitched cry, hypertonia, arching of the neck (retrocollis) and back (opisthotonus), fever
Phase
Advanced
Features
Deep stupor or coma, seizures, apnoea
Kernicterus (Chronic Bilirubin Encephalopathy)
- Choreoathetoid cerebral palsy
- Sensorineural hearing loss
- Upward gaze palsy
- Dental enamel defects
- Intellectual disability in some children
Diagnosis
| Investigation | Purpose |
|---|---|
| Total serum bilirubin with direct (conjugated) fraction | Confirms level and type |
| Transcutaneous bilirubin | Non-invasive screening |
| Maternal and baby blood group and Rh type | Suspected Rh or ABO incompatibility |
| Direct Coombs test | Immune haemolysis |
| Haemoglobin, haematocrit, reticulocyte count, peripheral smear | Haemolysis, spherocytes, polycythaemia |
| G6PD assay | G6PD deficiency |
| Sepsis screen | Suspected infection |
| Thyroid function | Prolonged jaundice |
| Liver function tests, ultrasound, hepatobiliary scan | Conjugated jaundice, suspected biliary atresia |
Investigation
Total serum bilirubin with direct (conjugated) fraction
Purpose
Confirms level and type
Investigation
Transcutaneous bilirubin
Purpose
Non-invasive screening
Investigation
Maternal and baby blood group and Rh type
Purpose
Suspected Rh or ABO incompatibility
Investigation
Direct Coombs test
Purpose
Immune haemolysis
Investigation
Haemoglobin, haematocrit, reticulocyte count, peripheral smear
Purpose
Haemolysis, spherocytes, polycythaemia
Investigation
G6PD assay
Purpose
G6PD deficiency
Investigation
Sepsis screen
Purpose
Suspected infection
Investigation
Thyroid function
Purpose
Prolonged jaundice
Investigation
Liver function tests, ultrasound, hepatobiliary scan
Purpose
Conjugated jaundice, suspected biliary atresia
Hour-specific bilirubin nomograms (such as the Bhutani nomogram and current American Academy of Pediatrics thresholds) are used to decide the need for phototherapy based on the baby's age in hours, gestational age and risk factors.
Management
General Measures
- Encourage frequent, effective breastfeeding
- Identify and treat the underlying cause
- Monitor bilirubin and the baby's clinical condition
- Check for danger signs of bilirubin encephalopathy
Phototherapy
| Aspect | Key Points |
|---|---|
| Mechanism | Blue-green light (about 460 to 490 nm) converts bilirubin into water-soluble isomers, including lumirubin, which are excreted in bile and urine without conjugation |
| Indication | Bilirubin above the age-specific threshold for gestation and risk |
| Care during phototherapy | Eye shields, maximum skin exposure, regular turning, temperature and hydration monitoring, continued feeding |
| Side effects | Dehydration, loose stools, skin rash, temperature instability, bronze baby syndrome in babies with conjugated hyperbilirubinaemia |
Aspect
Mechanism
Key Points
Blue-green light (about 460 to 490 nm) converts bilirubin into water-soluble isomers, including lumirubin, which are excreted in bile and urine without conjugation
Aspect
Indication
Key Points
Bilirubin above the age-specific threshold for gestation and risk
Aspect
Care during phototherapy
Key Points
Eye shields, maximum skin exposure, regular turning, temperature and hydration monitoring, continued feeding
Aspect
Side effects
Key Points
Dehydration, loose stools, skin rash, temperature instability, bronze baby syndrome in babies with conjugated hyperbilirubinaemia
Exchange Transfusion
- Used for very high or rapidly rising bilirubin despite phototherapy, or with signs of bilirubin encephalopathy
- A double-volume exchange removes bilirubin and antibody-coated red cells and corrects anaemia
- Complications include infection, electrolyte imbalance, thrombosis and cardiac arrhythmias
Other Treatments
- Intravenous immunoglobulin in immune haemolytic disease (Rh or ABO) to reduce the need for exchange transfusion
- Biliary atresia: early Kasai portoenterostomy gives the best results; later cases may need liver transplantation
Complications
- Acute bilirubin encephalopathy
- Kernicterus with permanent neurological damage
- Sensorineural hearing loss
- Complications of exchange transfusion
- Liver cirrhosis in untreated biliary atresia
Prevention
- Anti-D immunoglobulin for Rh-negative mothers, given antenatally and after delivery of an Rh-positive baby, to prevent Rh isoimmunisation
- Blood grouping in pregnancy
- Early and frequent breastfeeding
- Bilirubin screening before discharge and follow-up of babies discharged early
- Awareness of the "stool colour card" to detect pale stools early
Prognosis
Physiological jaundice resolves without harm. Pathological jaundice has an excellent outcome when detected and treated early. Kernicterus is permanent, so prevention through timely screening and treatment is essential.
Quick Viva Questions
Q: At what serum bilirubin level does jaundice become visible in newborns? A: About 5 mg/dL.
Q: When is neonatal jaundice always pathological? A: When it appears within the first 24 hours of life.
Q: How does phototherapy work? A: It converts bilirubin into water-soluble isomers, such as lumirubin, which are excreted without needing conjugation.
Q: Which part of the brain is most affected in kernicterus? A: The basal ganglia, especially the globus pallidus.
Q: What stool colour suggests biliary atresia? A: Pale or clay-coloured stools, with dark urine.
Q: What is the typical blood group combination in ABO incompatibility? A: Mother group O with baby group A or B.
How Neonatal Jaundice Appears in MBBS University Exams
Typical question styles (not attributed to specific papers or years):
- "Differentiate physiological from pathological jaundice. Discuss the approach to a newborn with jaundice." (Long essay, Paediatrics)
- "Discuss the causes and management of neonatal hyperbilirubinaemia." (Long essay)
- "Write a short note on phototherapy." (Short note)
- "Write a short note on kernicterus." (Short note)
- "Write a short note on Rh isoimmunisation and its prevention." (Short note, Obstetrics)
- "Write a short note on exchange transfusion." (Short note)
Frequently Asked Questions
What is the difference between physiological and pathological neonatal jaundice?
Physiological jaundice appears after 24 hours, peaks around days 3 to 5 in term babies and resolves within about 2 weeks. Pathological jaundice appears in the first 24 hours, rises rapidly, exceeds phototherapy thresholds, persists or involves raised conjugated bilirubin.
What is the difference between breastfeeding jaundice and breast milk jaundice?
Breastfeeding jaundice occurs in the first week because of inadequate milk intake. Breast milk jaundice appears later and peaks in the second or third week in a well, thriving baby.
Can I download the neonatal jaundice PPT for my presentation?
Yes. Use the Download PPT button at the top of this page. The GeckoMed app also gives offline access to the slides and notes.
Try Gecko Med
Practice smarter with the app behind these resources.
Revise high-yield topics, solve previous year questions, and keep your MBBS prep moving in one place.