Origins of the discipline ‘neonatal haematology’, 1925–75

In every modern neonatal intensive care unit (NICU), haematological problems are encountered daily. Many of these problems involve varieties of anaemia, neutropenia or thrombocytopenia that are unique to NICU patients. A characteristic aspect of these unique problems is that, if the neonate survives, the haematological problem will remit and will not recur later in life, nor will it evolve into a chronic illness (although the problem might occur in a future newborn sibling). This characteristic comes about because the common haematological problems of NICU patients are not genetic defects but are environmental stresses (such as infection, alloimmunization or a variety of maternal illnesses) that are imposed on a developmentally immature haematopoietic system. In the USA, and in some parts of Europe, the unique haematological problems that occur among NICU patients are diagnosed and treated by neonatologists, not by paediatric haematologists. Although these haematological conditions were generally first described by haematologists, the conditions occur, obviously, in neonates. Thus, the neonatologist, who is familiar with intensive care management of neonates, has also become familiar with the diagnosis and management of the neonate's common haematological disorders. A growing number of neonatologists have sought specific additional training in haematology, with the goals of discovering the mechanisms underlying the unique haematological problems of NICU patients and improving the management and outcome of the patients who have these conditions. These physicians have remained as neonatologists and they do not practice paediatric haematology, although their research contributions certainly come under the purview of haematology, or more precisely under the discipline of `neonatal haematology'. In many places in Europe, it is the haematologists rather than the neonatologists who have an academic and clinical interest in neonatal haematology. The roots of the discipline of neonatal haematology can be traced to the early application of haematological methods to animal and human embryos and fetuses, such as found in the reports of Maximow (1924) and Wintrobe & Schumacker (1936). The clinical underpinnings of this discipline include reports of anaemia (Fikelstein, 1911) and jaundice (Blomfeld, 1901; YlppoÈ, 1913) among neonates. Most of the clinical observations upon which neonatal haematology was founded were published during the 50year period 1925±75. That is the period that will be examined in this review. Owing to page limitations, this report cannot review all reports from that 50-year period that are relevant to neonatal haematology and, therefore, an attempt was made to review representative key publications that laid the framework for understanding pathogenesis and treatment. The review is not intended as a state-ofthe-art review of neonatal haematology, but rather as a historical review, covering the period 1925±75, and centreing on a few pivotal developments. The review is organized into six topics: (1) The beginnings of academic neonatology, (2) New textbooks and new journals, (3) Normal haematological values of preterm and term infants, (4) The neutropenia of neonatal sepsis, (5) The anaemia of prematurity, and (6) Other significant advances in neonatal haematology during this 50-year period.