Over a period of many decades, disorders of the blood in the fetus and neonate have captured the interest of hematologists and pediatricians. The first textbook devoted exclusively to Clinical Hematology, written by Dr. Maxwell M. Wintrobe in 1943, included discussions of blood cell counts, anemias, and hemorrhagic problems of newborn infants, and provided a brief review of neonatal thrombocytopenia. At that early time, the clinical importance of neonatal hematology was clear, as erythroblastosis fetalis affected up to 1% of neonates and carried a mortality rate of up to 50%. Hemorrhagic disorders of neonates had been recognized from antiquity, but classification, pathogenesis, management, and prevention of these conditions were obscure.
Incredible advances in neonatal hematology have come about in the 70 years since Dr. Wintrobe’s first edition was published. These advances were brought about largely as a result of applying new methods to study blood. Initially these methods involved morphologic examination of the blood and marrow of fetuses and neonates, followed by accurate quantification of the blood elements, and advances in in vitro hematopoietic development using tissue culture. More recent advances have come about by applying genetic methodologies to understand hematologic development and regulation, and using large historic cohorts and prospective clinical trials methods to assess potentially useful hematologic interventions including transfusions and growth factor administration.
This issue of Seminars in Neonatal Hematology includes up-to-date summaries of selected aspects of these advances, authored by neonatologists with special interest, training, and experience in hematology. The authors of each article have enjoyed many years of collaborating with each other, and with other experts, and with clinical trials groups. Their reviews contained herein begin with the expected reference ranges for hematological values of neonates organized according to gestational and post-natal ages, as assembled and tested using large multicentered data sets. Subsequent chapters deal with erythrocytes, and include the topics of erythropoiesis in the human fetus and neonate, the use of human recombinant erythropoietin in the NICU, and oxidative injury in neonatal erythrocytes. Another update deals with evaluating neutropenia and neutrophilia in preterm infants. Other chapters involve advances in neonatal transfusion medicine, including the association between erythrocyte transfusion and necrotizing enterocolitis, the risks and benefits of erythrocyte transfusion therapy, and a consistent approach to platelet transfusions in the NICU.
It is our hope that this collection of new information and updates will be of value to each reader considering the best practices to employ for their neonatal patients. We thank our collaborators, spouses, family members, nurses, secretaries, administrators, and NICU patients and families for their support of our efforts to develop, organize, and present this information. It is our belief that careful and diligent work toward discovering and applying new knowledge in neonatal hematology will be a continuous source of improving the outcomes of ill or prematurely delivered neonates everywhere.