Prothrombin Deficiency of the Newborn

Abstract

Studies were made on the plasmas of 12 newborn infants, who had not received vit. K, and whose plasmas exhibited prolonged prothrombin times. These plasmas were mixed with plasma of normal adults, stored adult plasma or serum, plasma of normal infants, or plasma of dicoumarolized adults and adults with liver disease. Mixtures from the first groups showed a marked restoration of prothrombin time, those from the 3rd group moderate restoration and those from the last group little, if any, restoration. From this it was concluded that the prothrombin deficiency of the newborn cannot be adequately explained as a simple deficiency of prothrombin. Although there may be some diminution of prothrombin, it appears that the plasma of the newborn is deficient in a factor accelerating the conversion of prothrombin to thrombin.