[The appearance of an inhibitor to clot formation in the plasma of the umbilical vein (author's transl)].

In 127 samples of the plasma from the umbilical vein obtained between one and five minutes after spontaneous normal vertex delivery, the coagulation inhibition was measured. The inhibition increases with increasing bearing down. There is no correlation between the duration of the second stage and the duration of the pregnancy. In gel-chromatography from plasma fractions of adults and newborns, prepared in the same manner, only in the newborn material a protein was found which inhibits coagulation. The significance of the coagulation inhibitor developed by the newborn in correlation to its maturity is discussed.