Developmental hemostasis: pro- and anticoagulant systems during childhood.

An understanding of developmental hemostasis is pivotal for optimal prevention, diagnosis, and treatment of hemostatic problems during childhood. The development of microassays in the early 1980s enabled researchers to delineate age-dependent features of the coagulation system and to establish reference ranges for healthy children of all age groups, from premature infants to adolescents. Based on the results from these studies, the hemostatic system in the young can be described as evolving, and yet functional, since healthy fetuses, infants, and children do not suffer hemorrhagic nor thromboembolic complications spontaneously or in the presence of minor challenges. Plasma concentrations of most pro- and anticoagulant proteins are decreased throughout childhood but provide an effective hemostatic balance on a lower level compared with adults. The current article describes the development of pro- and anticoagulant systems throughout childhood.