Neonatology
Neonatology is the subject where paediatric reasoning stops resembling adult medicine altogether. The organisms are different, the drug doses are different, and the normal values are different, but none of that is the real difficulty.
The real difficulty is that a newborn is not a person who has been alive for a day. A newborn is a fetus in the middle of an abrupt and total change of physiology, and the problems that arise are problems of that change.
1. The Newborn Is a Transition, Not a Small Child
At the moment of birth, several independent physiological systems must switch over within minutes.
| Transition | From | To |
|---|---|---|
| Respiratory | Fluid-filled lungs, no gas exchange | Air-filled lungs, all gas exchange |
| Circulatory | Parallel circulation with three shunts | Series circulation, shunts closed |
| Thermal | Maternal temperature maintained free | Own heat production against a cold room |
| Metabolic | Continuous placental glucose | Intermittent feeding with own gluconeogenesis |
| Bilirubin | Cleared by the maternal liver | Cleared by an immature neonatal liver |
The organising tool is to name the failed transition first, and the diagnosis follows. Respiratory distress means the lung transition failed. Cyanosis unresponsive to oxygen means the circulatory transition failed. Hypothermia, hypoglycaemia and jaundice are each the corresponding transition failing.
Sepsis is the exception, and that is precisely why it is dangerous. Neonatal sepsis does not have a presentation of its own; it imitates all of the others. A septic newborn presents with respiratory distress, or hypothermia, or hypoglycaemia, or jaundice, or simply with not feeding.
The practical consequence is a rule that governs the whole subject: in a newborn who deteriorates, sepsis is considered alongside whatever else is being treated, not after it has been excluded.
2. Resuscitation at Birth
Around one newborn in ten needs some help to begin breathing, and most of them need only drying, warmth and stimulation.
The initial assessment asks three questions: is the baby term, is the tone good, and is the baby breathing or crying? If all three are yes, the baby stays with the mother.
Delayed cord clamping, for at least one minute in a vigorous newborn, is now standard. It transfers a substantial additional volume of placental blood, which improves iron stores at six months and reduces the need for transfusion in preterm infants.
Routine suctioning is not performed, including in meconium-stained liquor when the baby is vigorous. It provokes bradycardia through vagal stimulation and wastes the golden minute.
The golden minute and what guides it
Ventilation must be established within the first minute of life. This is the single most important intervention in newborn resuscitation, because the overwhelming majority of neonatal arrests are respiratory rather than cardiac in origin.
Heart rate is the primary indicator of adequate ventilation. A rising heart rate means the lungs are being inflated; a heart rate that is not rising means they are not, whatever the chest appears to be doing.
When ventilation is ineffective, the corrective steps are remembered as MRSOPA: mask adjustment, reposition the head, suction if needed, open the mouth, increase pressure, and consider an alternative airway.
Term infants are resuscitated with room air, not 100 percent oxygen. Trials showed lower mortality with air, and the reason is that hyperoxia generates free radicals in tissue that has just been ischaemic. Preterm infants are started on a low blended concentration and titrated to target saturations.
Chest compressions are begun only if the heart rate remains below 60 despite effective ventilation, at a ratio of 3 compressions to 1 breath.
3. Classifying the Newborn
Two independent axes are used, and confusing them is a standard exam trap.
| By weight | By gestation |
|---|---|
| Low birth weight: under 2,500 g | Preterm: under 37 weeks |
| Very low birth weight: under 1,500 g | Term: 37 to under 42 weeks |
| Extremely low birth weight: under 1,000 g | Post-term: 42 weeks or more |
A low birth weight baby may be preterm, growth restricted, or both, and the management differs completely. The preterm baby has immature organs; the growth-restricted term baby has mature organs and a nutritional deficit.
Growth restriction itself divides by timing. Symmetric restriction, in which weight, length and head circumference are all reduced proportionately, indicates an insult early in pregnancy, such as a chromosomal disorder or congenital infection.
Asymmetric restriction, in which weight is reduced but head circumference is relatively preserved, indicates a late insult, typically placental insufficiency. The head is spared because blood flow is redistributed to the brain, which is the same priority hierarchy that governs postnatal growth.
Growth-restricted babies are at particular risk of hypoglycaemia, polycythaemia, hypothermia and meconium aspiration.
4. The Thermal Transition
A newborn loses heat rapidly and cannot generate it the way an adult does. Newborns do not shiver. They rely on non-shivering thermogenesis in brown adipose tissue, which is present in limited quantity and is largely absent in the preterm infant.
Heat is lost by evaporation from wet skin, conduction to cold surfaces, convection to moving air, and radiation to cold walls. All four are addressed by drying immediately, removing the wet cloth, and skin-to-skin contact.
Cold stress is not merely uncomfortable; it is metabolically expensive. Generating heat consumes glucose and oxygen, so the cold baby becomes hypoglycaemic and hypoxic, and acidosis follows. In the preterm infant, cold stress alone can precipitate respiratory deterioration.
Kangaroo mother care
Kangaroo mother care means continuous skin-to-skin contact between mother and baby with exclusive breastfeeding. It maintains temperature, promotes feeding, reduces infection and improves survival.
The important recent change is in timing. The WHO immediate kangaroo mother care trial, conducted in Indian and African units, found a mortality reduction of roughly 25 percent in infants weighing 1.0 to 1.799 kg when contact began immediately rather than after stabilisation, and it was stopped early for benefit.
WHO now recommends beginning kangaroo mother care immediately after birth, without waiting for the baby to be stabilised, which reverses long-standing practice. Pooled analysis with the Ugandan and Gambian trials gives a 19 percent reduction in 28-day mortality.
5. The Respiratory Transition
| Condition | Typical baby | Mechanism | Course |
|---|---|---|---|
| Respiratory distress syndrome | Preterm | Surfactant deficiency | Worsens over 24 to 48 hours |
| Transient tachypnoea | Term, often caesarean | Delayed clearance of lung fluid | Settles within 24 to 72 hours |
| Meconium aspiration | Term or post-term | Airway obstruction and chemical pneumonitis | Variable, may cause hypertension |
Surfactant lowers alveolar surface tension and prevents collapse at end-expiration. Without it the preterm lung collapses with every breath and must be reinflated with each one, which is why the work of breathing is so high and why the chest radiograph shows a diffuse ground-glass pattern with air bronchograms.
Antenatal corticosteroids given to the mother are the single most effective intervention, because they accelerate surfactant production before delivery rather than replacing it afterwards.
After birth, early continuous positive airway pressure keeps alveoli open through expiration and reduces the need for intubation. Surfactant is given when distress is significant, increasingly by minimally invasive techniques that avoid mechanical ventilation altogether.
Transient tachypnoea is the mimic to recognise, since it occurs in term babies, is commoner after caesarean section without labour because labour itself promotes fluid clearance, and resolves on its own with supportive care.
6. The Circulatory Transition
The fetal circulation runs in parallel through the ductus venosus, foramen ovale and ductus arteriosus. At birth, lung expansion drops pulmonary vascular resistance and cord clamping raises systemic resistance, reversing the pressure gradient and closing the shunts functionally.
Persistent pulmonary hypertension of the newborn is the failure of that pressure reversal. Pulmonary resistance stays high, blood continues to shunt right to left, and the baby is profoundly cyanosed with a striking difference between pre-ductal and post-ductal saturations.
Cyanosis that does not improve with 100 percent oxygen indicates a right-to-left shunt, either persistent pulmonary hypertension or cyanotic congenital heart disease, rather than lung disease.
Some cardiac lesions are duct-dependent, meaning that survival depends on the ductus arteriosus staying open. In these babies, prostaglandin E1 is started to keep the duct open, which is the opposite of the usual instinct to close it.
Pulse oximetry screening of every newborn before discharge, comparing right hand and foot, detects critical congenital heart disease that examination misses, and is worthwhile precisely because these babies look well until the duct closes.
7. The Glucose Transition
The fetus receives glucose continuously across the placenta and produces almost none. At birth that supply stops abruptly, and the baby must mobilise glycogen and begin gluconeogenesis while feeding intermittently.
The babies who fail this transition are predictable: the preterm and growth-restricted, who have inadequate glycogen stores; the infant of a diabetic mother, who is hyperinsulinaemic; the large baby; the cold baby; and the septic baby.
Infants of diabetic mothers are hypoglycaemic because maternal hyperglycaemia drove fetal hyperinsulinism, and the insulin persists after the glucose supply stops. They are also macrosomic, at risk of shoulder dystocia, and prone to polycythaemia and hypocalcaemia.
Neonatal hypoglycaemia is frequently asymptomatic, which is why at-risk babies are screened rather than watched. When symptoms occur they are non-specific: jitteriness, poor feeding, lethargy, apnoea or seizures.
Asymptomatic hypoglycaemia is treated by feeding and rechecking; symptomatic hypoglycaemia or seizures require intravenous dextrose. Prolonged untreated hypoglycaemia causes permanent neurological injury, and the occipital cortex is characteristically affected.
8. The Bilirubin Transition
Almost every newborn becomes jaundiced to some degree, for reasons that are all consequences of transition. Red cell mass is high and fetal red cells are short-lived, so bilirubin production is high. The hepatic conjugating enzyme is immature. Enterohepatic circulation is increased because the gut is not yet colonised.
The single most useful discriminator is timing.
| Timing | Interpretation |
|---|---|
| Within 24 hours | Always pathological; think haemolysis or sepsis |
| Day 2 to day 5, peaking then falling | Physiological |
| Beyond 14 days in a term infant | Prolonged; must fractionate the bilirubin |
Jaundice within the first 24 hours is never physiological, because a normal liver cannot fall that far behind that quickly. Rhesus and ABO incompatibility, glucose-6-phosphate dehydrogenase deficiency and sepsis are the causes to consider.
Two feeding-related patterns are confused constantly. Breastfeeding jaundice appears early and is caused by insufficient intake, with dehydration and increased enterohepatic circulation; the treatment is more effective feeding, not less. Breast milk jaundice appears later, persists for weeks, and occurs in a thriving baby; breastfeeding continues.
In prolonged jaundice the bilirubin must be fractionated, because conjugated hyperbilirubinaemia is always pathological. Biliary atresia is the diagnosis that must not be missed, since outcome depends on surgery being performed early, and the clues are pale stools and dark urine.
Kernicterus is bilirubin encephalopathy, in which unconjugated bilirubin crosses into the basal ganglia. Acute features are lethargy, poor feeding, a high-pitched cry and opisthotonus; survivors develop choreoathetoid cerebral palsy, deafness and upward gaze palsy.
Phototherapy converts bilirubin to water-soluble isomers excretable without conjugation. Exchange transfusion is reserved for levels approaching neurotoxicity or for rapidly rising haemolytic jaundice.
9. Neonatal Sepsis
Sepsis is divided by timing of onset, and the division reflects where the organism came from.
Early-onset sepsis, within 72 hours, is acquired from the maternal genital tract, and its risk factors are obstetric: prolonged rupture of membranes, maternal fever, chorioamnionitis, prematurity and unclean delivery. It typically presents as pneumonia or fulminant septicaemia.
Late-onset sepsis, after 72 hours, is acquired from the environment, meaning hands, equipment and catheters, and it more often presents as septicaemia or meningitis.
The organism profile in India differs from Western textbooks and this is examined. Group B Streptococcus dominates Western early-onset sepsis, whereas Indian data are dominated by Gram-negative organisms, particularly Klebsiella, Escherichia coli and Acinetobacter, with Staphylococcus aureus also prominent, and resistance is a major problem.
The presentation is the absence of a presentation. A baby who is not feeding well, who is less active than yesterday, whose temperature is unstable in either direction, is septic until proved otherwise. Mothers report this before clinicians detect it.
10. Birth Asphyxia and Neonatal Encephalopathy
Perinatal asphyxia causes hypoxic ischaemic encephalopathy, graded by the Sarnat classification into mild, moderate and severe, on the basis of consciousness, tone, reflexes, autonomic function and seizures.
Multiple organs are injured, not only the brain: acute kidney injury, myocardial dysfunction, hepatic derangement and necrotising enterocolitis all occur.
Therapeutic hypothermia is standard care in high-income settings for moderate or severe encephalopathy, and it is not recommended in India. The HELIX trial, conducted in tertiary units in India, Sri Lanka and Bangladesh with servo-controlled cooling, found no reduction in death or disability at 18 months and a significant increase in death alone.
This finding matters beyond the fact itself. The participating units had invasive ventilation, cardiovascular support and 3 Tesla magnetic resonance imaging, so if cooling was harmful under those conditions it cannot be assumed safe elsewhere. An intervention that works in one health system is not automatically transferable to another, and this is one of the cleanest demonstrations of that principle in modern paediatrics.
11. Newborn Care Programmes in India
India's neonatal mortality rate has fallen to around 19 to 20 per 1,000 live births, but the neonatal period now accounts for the majority of under-five deaths, so further progress in child survival depends almost entirely on newborn care.
Facility-based care is organised in a tiered structure: newborn care corners in every delivery room, newborn stabilisation units at community health centres, and special newborn care units at district hospitals.
Home-based newborn care uses accredited social health activists to visit at fixed intervals during the first six weeks, weighing the baby, checking for danger signs, supporting breastfeeding and referring.
The rationale is straightforward. Most neonatal deaths in India occur at home in the first week, from prematurity, sepsis and asphyxia, and the visits place a trained person in the house during exactly that window.
12. Worked Examples
Example 1. A term baby born by elective caesarean has tachypnoea from birth, mild grunting, and a chest radiograph showing prominent perihilar streaking and fluid in the horizontal fissure. Diagnosis?
Transient tachypnoea of the newborn, caused by delayed clearance of fetal lung fluid. It is commoner after caesarean section without labour, because labour itself promotes fluid absorption. It settles within 24 to 72 hours with supportive care, unlike respiratory distress syndrome, which worsens over the first 24 to 48 hours and occurs in preterm babies.
Example 2. A baby is cyanosed at 6 hours with saturations of 70 percent that do not improve on 100 percent oxygen. Chest radiograph and breath sounds are unremarkable. What does this indicate?
A right-to-left shunt, meaning either cyanotic congenital heart disease or persistent pulmonary hypertension, rather than lung disease. Failure to respond to oxygen is the discriminator, because blood bypassing the lungs entirely cannot be oxygenated by raising the inspired concentration. Pre-ductal and post-ductal saturations should be compared, and if a duct-dependent lesion is suspected, prostaglandin E1 is started to keep the duct open.
Example 3. A term baby is jaundiced at 18 hours of age. Mother is O positive, baby is A positive. What is the significance of the timing?
Jaundice within the first 24 hours is always pathological, since a normal liver cannot fall that far behind that quickly. The setup describes ABO incompatibility with haemolysis. Glucose-6-phosphate dehydrogenase deficiency, rhesus disease and sepsis are the other causes. Investigation and treatment are urgent, because haemolytic jaundice rises rapidly and kernicterus is preventable only before it occurs.
Example 4. A baby in a district hospital has moderate hypoxic ischaemic encephalopathy at 4 hours of age. Should cooling be started?
No. The HELIX trial found that therapeutic hypothermia in Indian, Sri Lankan and Bangladeshi tertiary units did not reduce death or disability at 18 months and significantly increased death. It is therefore not recommended in this setting even where facilities exist. Management is supportive: normothermia, seizure control, glucose and electrolyte maintenance, and attention to the other organs injured by the asphyxial insult.
Summary
The newborn is a transition, not a small child, and naming the failed transition names the diagnosis.
Sepsis is the exception that imitates every transition failure, so it is considered alongside other diagnoses rather than after them.
Establish ventilation within the golden minute, use heart rate as the guide, delay cord clamping, do not suction routinely, and resuscitate term babies with air.
Low birth weight and prematurity are different axes. Symmetric growth restriction means an early insult; asymmetric means late placental insufficiency.
Newborns do not shiver, so cold stress consumes glucose and oxygen and causes deterioration in its own right.
Kangaroo mother care now begins immediately, before stabilisation, on the strength of a WHO trial showing roughly 25 percent lower mortality.
Surfactant deficiency causes respiratory distress syndrome in the preterm; delayed fluid clearance causes transient tachypnoea in the term caesarean baby.
Cyanosis unresponsive to oxygen means a right-to-left shunt, and duct-dependent lesions need prostaglandin to keep the duct open.
Jaundice within 24 hours is never physiological, and prolonged jaundice must be fractionated to exclude biliary atresia.
Indian neonatal sepsis is predominantly Gram-negative, unlike the group B Streptococcus of Western texts.
Therapeutic hypothermia is not recommended in India, because HELIX showed increased mortality even in well-equipped tertiary units.
