Translational aspects of developmental hemostasis: infants and children are not miniature adults and even adults may be different

Developmental hemostasis is a concept that is now well accepted amongst experts in the field of hemostasis, but which is potentially under-recognized by many clinicians and scientists working in the field of medicine and diagnostics. Developmental hemostasis as regards to secondary hemostasis, meaning the ‘blood clotting’ aspects that involve the many coagulation factors, the often-called coagulation ‘cascade’, and the eventual conversion of fibrinogen to fibrin, was spearheaded by Andrew et al. (1,2), and more recently confirmed and formalized by Monagle, Ignjatovic and colleagues (3,4). For example, (I) the concentration of vitamin K dependent coagulation factors, thrombin generation and clot lysis are all reduced in neonates compared with older children; (II) for the natural anticoagulants, the level of antithrombin is reduced in neonates, but reaches that of adults after around six months, whereas, in contrast, protein S and protein C is markedly reduced in neonates and both increase throughout childhood, although levels do not reach those of adults until adolescence (Table 1). Indeed, the concept of hemostasis developing from the very young, including newborns and infants, onwards to childhood, and then adulthood, and even further as adults age, is now a well-established fact (5,6).