Summary
The last phase of the clotting mechanisms was investigated in cord blood of 118 mature
newborns.
The most prominent finding was a prolonged thrombin time, not due to heparin. It was
accompanied in most cases by a low fibrinogen and in some by a gelatinous appearance
of the clot and a paracoagulation of the serum. This association was found to be usually
due to in vitro fibrinogenolysis with consequent appearance of fibrinogen split products.
In 9 cases the prolonged thrombin time was not obviously due to fibrinogen degradation
products. The possibilities of the presence of high molecular weight fibrinogen degradation
products or of a special characteristic of cord blood fibrinogen leading to a delayed
fibrinogen-fibrin conversion are considered.