Neonatal Haematology. Irene Roberts

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when the manual and automated methods are compared.75 The number of NRBC in the peripheral blood falls rapidly over the first week of life and these cells are no longer seen after the second week of life. By contrast, circulating erythroblasts are increased in a variety of conditions in neonates and their presence can therefore be useful diagnostically because they usually indicate increased erythropoiesis driven either by anaemia or by chronic intrauterine hypoxia, for example due to IUGR (Table 1.4 and Fig. 1.10). It should be noted that NRBC also appear in the peripheral blood as part of a leucoerythroblastic picture, most typically in response to acute perinatal hypoxia (Fig. 1.11).76,77

      Red blood cell morphology

Response to anaemia: haemolytic disorders
Haemolytic disease of the newborn (especially due to anti‐D and anti‐c)
α thalassaemia major (occasionally, haemoglobin H disease)
Severe congenital dyserythropoietic anaemia (e.g. due to KLF1 mutations)
Rare severe red cell enzyme deficiencies (e.g. pyruvate kinase deficiency or glucose phosphate isomerase deficiency)
Rare severe red cell membranopathies (e.g. hereditary stomatocytosis or autosomal recessive hereditary spherocytosis)
Response to anaemia: blood loss (mainly acute)
Fetomaternal haemorrhage
Placental abruption
Large cephalohaematoma
Haemorrhage into major organs, e.g. liver Twin‐to‐twin transfusion (donor twin)
Response to hypoxia
Chronic in utero hypoxia:
Intrauterine growth restriction
Maternal hypertension
Maternal diabetes mellitus
Down syndrome (mechanism unclear)
Acute perinatal hypoxia:
Hypoxic ischaemic encephalopathy (leucoerythroblastic)
Neoplasms
Transient abnormal myelopoiesis in Down syndrome*
Congenital leukaemia (non‐Down syndrome)
Other
Recovery phase of parvovirus B19 infection

      * The increase in circulating erythroblasts is even higher in Down syndrome neonates with transient abnormal myelopoiesis than in Down syndrome neonates in general.

Photo depicts a blood film showing features of hyposplenism resulting from intrauterine growth restriction: (a) low power showing anisocytosis, poikilocytosis, target cells and some fragments (MGG, ×40); (b) high power, two Howell–Jolly bodies are apparent (MGG, ×100). Photo depicts a blood film from a preterm neonate (born at 25 weeks’ gestation) on the day of birth showing a leucoerythroblastic picture with NRBC, a myelocyte and promyelocyte as well as toxic granulation of the neutrophils and red cell morphology typical of an extremely preterm neonate. Photo depicts impact of postnatal age on red cell morphology; blood films from: (a) healthy term baby; (b) neonate at a postnatal age of 4 weeks.

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