MATERNAL AND CORD-BLOOD HEMOSTASIS AT DELIVERY

Today we know that the coagulation system of the neonate differs in ma ny ways from that of the adult system. We see a general reduction of t he coagulation factors II-XIII (except VIII), the fibrinogen and of th e coagulation inhibitors ATIII, protein C and heparin cofactor II at t he same time. In addition the newborns show different levels of the co agulation factors for premature and full-term infants. This situation necessitates the generation of not one, but several, reference ranges for the Various components of the hemostatic system. While the above-m entioned factors of the coagulation and fibrinolytic system of the new born are well studied, our knowledge of others is still lagging behind that of the adult. That applies to the vWF and PAI and even more to D -Dimer. Our aim was to collect some data for VWF, PAI and D-Dimer to c omplete the understanding of the physiology of the hemostatic system i n the newborn. Therefore we used the blood samples from 59 newborns an d their mothers to obtain a number of different components of the coag ulation and fibrinolytic system. Besides some rheological parameters ( erythrocyte aggregation, plasma viscosity) we measured the aPTT, PT an d the plasma levels of ATIII, fibrinogen and protein C (PC). But we pa id special attention to the plasma levels of von Willebrand factor (vW F), plasma activator inhibitor (PAI) and D-Dimer. The blood samples we re collected From the umbilical cord and the cubital vein of the mothe r immediately after delivery, anti-coagulated, centrifuged and stored until measurement at -70 degrees C. ATIII, aPTT, PT and fibrinogen wer e measured by the clotting technique test on the Chromotime(R) (Behrin g, Marburg, Germany). D-Dimer, vWF and protein C were determined with a commercially available ELISA obtained from Boehringer Mannheim (Mann heim, Germany). PAI activity was measured by a two-stage amiolytic met hod (Behring, Marburg). Besides the known differences of the neonatal hemostatic components to their mothers, such as a prolonged aPTT (52.1 9 s +/- 13.4 newborn, 35.26 s +/- 4.2 mother), reduced PT (64.34 s +/- 20.15 vs. 91.03 s +/- 1.25), ATIII (83.36% +/- 24.42 vs. 92.58% +/- 1 1.43) and fibrinogen (156.05 mg/dl +/- 91.68 vs. 344 mg/dl +/- 55.25), we found some peculiarities. The newborns show a clear reduction in t he vWF (97.79 ng/ml +/- 36.33 vs. 183.43 ng/ml +/- 16.03) as well as t he PAI (0.846 U/ml +/- 1.44 vs. 7.652 U/ml +/- 0.764). D-Dimer levels in the umbilical cord samples (1514.02 ng/ml +/- 953.56) are clearly p rolonged in contrast to the maternal levels (740.2 ng/ml +/- 139.68). We were also able to find a difference of these factors related to ges tational age. Premature infants showed a clearly higher lever of PAI ( 2.2 U/ml +/- 2.86 vs. 0.69 +/- 1.13; p = 0.0136) compared with full-te rm infants, as well as significantly lower levels of ATIII (48.8% +/- 23.19 vs. 86.62 +/- 22.04; p = 0.0006) and protein C (25.33% +/- 9.37 vs. 35.73 +/- 7.53; p = 0.0027). D-Dimer, vWF, fibrinogen and the rheo logical parameters are similar This seems to show an increased tendenc y for bleeding with the premature infant. Newborns show a balance of t he coagulation system solely on a lower level. This is due to the gene ral reduction of the coagulation factors with a reduction of the coagu lation inhibitors at the same time. The physiologically low level of t he vitamin K dependent and other coagulation factors and ATIII leads t o a prolonged aPTT and reduced PT of the newborn. As well as these dif fer ences, known from literature, we found the following specialities: lower vWF and PAI and higher D-Dimer levels of the newborn compared w ith their mothers.