Neonatal coagulation disorders

Abstract

Immaturity of hemostasis and its' relatively poor functional reserve are reasons for the increased incidence of hemostatic disorders in newborns. Hemostatic disorders in newborn period can present either as hereditary or acquired, with poor possibility to make a distinction between them, because of sampling and interpretation difficulties of hemostatic tests in newborns. The aim of the review is to present some data on the diagnosis and the treatment of neonatal hemostasis, particularly of coagulation disorders and thromboembolic events. Hemostatic disorders account for 1% of all admissions to the neonatal wards, and they have been found on post mortem examinations in 40% of newborns. Thrombocytopenia (platelet count < 150×109/l) is present in 1-5%, and severe thrombocytopenia (platelet count < 50×10 9/l) occurs in 0,1-0,5% of newborns at birth. It develops in 22-35% of all babies admitted to the neonatal intensive care units (NICU) and in up to 50% of newborns who require intensive care after their admission to NICU. About 20% of these episodes of thrombocytopenia are severe, which means that 8% of preterm and 6% of all neonates admitted to NICU have severe thrombocytopenia. Congenital deficiency of coagulation factors rarely manifests in neonates, while acquired coagulopathy, especially that connected with vitamin K dependent factors deficiency, are more frequent. Vitamin K deficiency bleeding occurs in 1,7% of newborns who did not receive postnatal vitamin K prophylaxis. In those newborns who were given only one per oral dose of vitamin K1, the relative risk of late onset bleeding occurrence due to vitamin K deficiency is 13,82. Estimated incidence of symptomatic venous thromboembolic events (VTE), support the general accepted view that the frequency in newborns is significantly less than for adults. The reported incidence of symptomatic VTE in newborns is 2,4 per 1,000 admissions to NICUs. An incidence of symptomatic neonatal thromboembolic events (central nervous system events included) is 0,51 per 10,000 births, with approximately half of the cases being VTE and half arterial. The differences of the treatment of coagulation disorders and thromboembolic events in the neonates are presented in the paper, with the special accent on the lack of controlled trials of the issue in the neonatal period, without the possibility do transpose the data from adult studies to neonates.