[Plasma levels of antithrombin III, thrombin-antithrombin III complex, alpha 2 plasmin inhibitor and plasmin alpha 2 plasmin inhibitor complex in normal and sick newborn infants].

Both bleeding and thrombosis are commonly seen in newborn infants because of their imbalance of coagulation and fibrinolysis system. In order to clarify some aspects of the hemostatic characteristics during neonatal period, we measured the levels of antithrombin-III (AT-III), thrombin AT-III complex (TAT), alpha 2-plasmin inhibitor (alpha 2PI) and plasmin alpha 2PI complex (PIC) in 137 normal and sick newborn infants. The results were as follows 1) AT-III levels in normal neonates were significantly low as compared with them in normal adults, and further lower levels were found in sick neonates. 2) TAT levels in sick neonates were significantly higher than those in either normal neonates and adults. In sick neonates, the incidence of abnormally high TAT values increased with DIC score points. 3) No significant difference of alpha 2PI level was seen between normal term neonates and adults. However, alpha 2PI levels in sick neonates were significantly low as compared with them in normal term neonates and adults. 4) PIC levels in either normal and sick infants were significantly higher than those in adults, but there was no significant difference in PIC levels between normal and sick newborn infants.