Neonatal Polycythaemia

Neonatal polycythaemia is usually defined as venous haematocrit 65% or greater. Increased red cell mass raises blood viscosity and can impair microvascular blood flow.

Risk factors include fetal growth restriction, maternal diabetes, placental transfusion and twin to twin transfusion.

Many infants are asymptomatic.

Possible features include:

• Plethora
• Lethargy
• Poor feeding
• Hypoglycaemia
• Respiratory distress
• Cyanosis
• Jaundice
• Seizures

Confirm an elevated capillary haematocrit using a venous haematocrit, because capillary values are commonly higher.

Check glucose and bilirubin.

Asymptomatic infants generally require hydration, feeding and monitoring.

Symptomatic infants with significant hyperviscosity and haematocrit above approximately 65% may require partial exchange transfusion under neonatal specialist supervision, generally aiming to reduce haematocrit toward approximately 50 to 55%.