Prothrombin and vitamin K deficiency in the newborn

Abstract

To detect any vitamin K deficiency at birth, prothrombin coagulant activity, antigen, and acarboxyprothrombin were examined in umbilical blood samples from 105 infants, 81 of whom constituted a normal group, while 24 had had minor gestational or perinatal complications. Values ranged from 8% to 70% (median: 34%) for P&P, from 17% to 70% (median: 40%) for prothrombin antigen, and from 7.11 to 7.51 (median: 7.29) for pH, no differences being discernible between normals and those with complications. Acarboxyprothrombin, indicating vitamin K deficiency, was detected in two cases, one from each group, but could not be correlated to either P&P or pH values. Conclusion: Vitamin K deficiency is rare among healthy, well-nourished Swedish neonates. The low values for prothrombin coagulant activity and for antigen would appear to be the result of decreased hepatic synthesis of the clotting factor molecule.

Key Words:

• Newborn
• prothrombin
• vitamin K deficiency