Polycythaemia is a commonly occurring neonatal disorder, which is characterized by a venous haematocrit ≥ 65%. It increases the blood viscosity and causes microcirculatory flow impairment in the end-organs. Causes of polycythaemia are multi-factorial, but the significant risk factors are maternal diabetes, SGA, LGA or post-term birth, infants with chromosomal abnormalities, and delayed clamping of the cord. Jaundice is not a recognized risk factor for polycythaemia.

Macrosomia can be defined as either a birth weight greater than 4kg or birth weight greater than 90% for the gestational age. Risk factors for macrosomia include maternal diabetes, excessive gestational weight gain, pre-pregnancy obesity, male gender, ethnicity, and advanced gestational age. Genetic conditions associated with macrosomia are Bardet-Biedl syndrome, Perlman syndrome, Beckwith-Wiedemann syndrome, and Prader-Willi syndrome. Silver-Russell syndrome is associated with intrauterine growth retardation and post-natal failure to thrive.

One of the most common congenital viral infections is cytomegalovirus infection. The infection is even commoner than the other widely known diseases like down’s syndrome and spina bifida. It is caused by herpesvirus type 5 and is diagnosed using PCR of saliva. The clinical features include failure to thrive, intellectual disability, epilepsy, and microcephaly. The most common clinical complication is sensorineural deafness. The drug of choice for the treatment of neonatal CMV infection is ganciclovir, an anti-viral drug that has shown to prevent deafness. Cytomegalic inclusion disease is diagnosed at birth with marked neurological disability, resulting from microcephaly, intracerebral calcifications, and cerebral atrophy.

Cytomegalovirus (CMV) is the most frequent cause of congenital infection worldwide, with an estimated incidence in developed countries of 0.6–0.7% of all live births.The clinical spectrum of congenital CMV infection varies widely, from the complete absence of signs of infection (asymptomatic infection) to potentially life-threatening disseminated disease. At birth, 85–90% of infected infants are asymptomatic, and 10–15% present with clinical apparent infection (symptomatic disease).The presentation in this latter group is a continuum of disease expression whose more common findings are petechiae, jaundice, hepatomegaly, splenomegaly, microcephaly, and other neurologic signs.

Neonatal hypoglycaemia is a serious condition that needs prompt attention and management. The accepted criteria to define neonatal hypoglycaemia is blood sugar levels less than 2.2mmol/L during the first 3 days of life and less than 2.5mmol/L later on. Multiple aetiologies and various risk factors are involved in causing hypoglycaemia in new-borns| the most common and important causes include prematurity, erythroblastosis fetalis, hypoxia at birth, sepsis, inborn errors of metabolism, hypopituitarism, and hyperinsulinism due to maternal diabetes. Inborn errors of metabolism that lead to persistent neonatal hypoglycaemia are maple syrup urine disease, glycogen storage disease, fatty acid enzyme deficiencies, and fructose intolerance. Phenylketonuria does not cause hypoglycaemia.

Usually, a total serum bilirubin level test is the only one required in an infant with moderate jaundice who presents on the second or third day of life without a history and physical findings suggestive of a pathologic process. Measurement of bilirubin fractions (conjugated vs unconjugated) in serum is not usually required in infants who present as described above. However, in infants who have hepatosplenomegaly, petechiae, thrombocytopenia, or other findings suggestive of hepatobiliary disease, metabolic disorder, or congenital infection, early measurement of bilirubin fractions is suggested. The same may apply to infants who remain jaundiced beyond the first 7-10 days of life, and to infants whose total serum bilirubin levels repeatedly rebound following treatment.

Neonatal hypoglycaemia is a common yet serious condition characterized by blood sugar levels less than 2.2mmol/L during the first 3 days of life and less than 2.5mmol/L later on. There are multiple aetiologies and various risk factors that lead to hypoglycaemia in new-borns like prematurity, sepsis, inborn errors of metabolism, and maternal diabetes- induced hyperinsulinism in the new-born. Among the inborn errors of metabolism, fatty acid oxidation defects can lead to persistent hypoglycaemia in new-borns. One such defect is the medium- chain acyl CoA dehydrogenase deficiency, which is the enzyme needed for the breakdown of medium- chain fatty acids.

Spontaneous intestinal perforation (SIP) of the new-born, also referred to as isolated perforation or focal intestinal perforation (FIP) of the new-born, is a single intestinal perforation that is typically found at the terminal ileum. SIP occurs primarily in preterm infants with very low birth weight (VLBW, birth weight <1500 g) and extremely low birth weight (ELBW, birth weight <1000 g), umbilical catheter placement, maternal drug use and twin-to-twin transfusion syndrome. SIP is a separate clinical entity from necrotizing enterocolitis, the most severe gastrointestinal complication of preterm infants.

After birth, the infant takes its first breath and is exposed to a myriad of stimuli. The pulmonary vessels dilate, and pulmonary vascular resistance (PVR) decreases remarkably while the systemic vascular pressure rises above the PVR. This allows blood from the right ventricle to enter the lungs for oxygenation. In most cases, this increased oxygenation, along with other factors, causes the ductal wall to constrict and the ductus arteriosus to close functionally. As left-sided pressures rise higher than right-sided pressures, the foramen ovale functionally closes. With the clamping of the umbilical cord and the cessation of blood flow, pressures in the portal sinus decrease. This causes the muscle in the sinus wall near the ductus venosus to contract. The lumen of the duct becomes filled with connective tissue, and, in two months, the ductus venosus becomes a fibrous strand embedded in the wall of the liver, thus establishing adult circulation.

Infants may require tracheal intubation if:- direct tracheal suctioning is required- effective bag-mask ventilation cannot be provided- chest compressions are performed- endotracheal (ET) administration of medications is desired- congenital diaphragmatic hernia is suspected, or – a prolonged need for assisted ventilation exists.