Laboratory aspects of hemostasis in neonates

Newborns have high risks of thrombotic and hemorrhagic complications. Despite the fact that the overall frequency of thrombosis and bleeding in the general population of neonates is low, the risks of both thrombosis and hemorrhage are significantly increased when a newborn has some complications, including prematurity. The mechanisms underlying the onset of thrombotic and hemorrhagic complications in newborns are not fully understood and remain controversial. The hemostasis in newborns drastically differs from adult hemostasis and even from hemostasis in children older than a year. Nevertheless, despite the presence of quantitative and qualitative differences of almost all parameters of the hemostasis system from the parameters of adults, healthy newborns as a whole have clinically normal functional hemostasis without a tendency to coagulopathy or thrombosis. Apparently, the neonatal hemostasis system is in some alternative "balance", which differs from the "balance" of hemostasis in adults. The issue regarding the stability of this balance is still open. Due to the peculiarities of the newborn's hemostasis, clinical laboratory diagnostics of the coagulation disorders is very difficult, and the attending physician is forced to focus exclusively on the clinical picture. This review provides basic information on the neonatal hemostasis system, as well as an attempt to critically evaluate existing laboratory tests in terms of applicability for this group of patients.