Roberts I., Chakravorty S.
© 2016, 2011, 2005 by JohnWiley & Sons Ltd. All rights reserved. The most common haematological problems in neonates are anaemia and thrombocytopenia. The majority of neonatal haematological disorders presenting in the first few days of life have their origin in utero and are unique to neonates., such as haemolytic disease of the newborn, Transient Abnormal Myelopoiesis in neonates with Down syndrome and haemorrhagic disease of the newborn. Limitations in sample size and vascular access mean that investigations should be carefully planned and parental sampling may be useful where inherited disease is suspected. Neonatal anaemia is best approached by considering simple clues to the mechanism of anaemia. Red cell aplasia due to Parvovirus B19 or Diamond Blackfan Anaemia is characterised by reticulocytopenia and an absence of circulating erythroblasts despite severe anaemia. The cause of haemolytic anaemia is usually clear from the results of the Direct Coombs test (DCT), red cell morphology and family history. Feto-maternal haemorrhage commonly presents as an unexpected severe anaemia at birth without jaundice and an early Kleihauer test is essential to make the diagnosis. For neonatal thrombocytopenia the most useful diagnostic clue is the natural history: early onset thrombocytopenia (<72 hours of age) is usually pregnancy-related while late-onset (>72 hours) is usually due to sepsis or necrotising enterocolitis.