[Blood coagulation and fibrinolytic factor activities in the amniotic fluid]

Plasma and 138 samples of amniotic fluid were obtained from 129 patients during the 15th to 39th pregnancy week and during parturition. Factor activities of the coagulation and fibrinolytic system were studied by means of enzymatic-kinetic measurement methods to differentiate the haemostaseological properties of the amniotic fluid. The factor X activity drops in the amniotic fluid during the third trimester and during parturition. The activities of plasminogen, alpha 1-antitrypsin, alpha 2-antiplasmin, antithrombin III and alpha 2-macroglobulin in the amniotic fluid do not change significantly during gestation and parturition. None of these factors seems to show any difference between the activities in the maternal placenta and in the amniotic fluid. The most striking change in activity was seen with prothrombin. There is a marked increase between the second and third trimester. In the maternal plasma the activity is relatively constant within the standard range of non-pregnant women. Further studies will be necessary to find out whether the increase in prothrombin activity in the amniotic fluid correlates with the increased surfactant production in the fluid and may thus be of diagnostic importance.