The prothrombin of the blood is elaborated in the liver. Andrus et al. (1939), and Warren and Rhoads (1939) produced experimental evidence in support, of this hypothesis. By total and partial hepatectomy in animals they produced a profound reduction in plasma prothrombin concentration which was unaffected by treatment with vitamin K and bile salts. It has been found essential to have vitamin K ...

Oral or parenteral administration of vitamin K is the accepted practice for prevention of early vitamin K deficiency bleeding (VKDB) in the newborn. However, vitamin K prophylaxis in the newborn continues to be a worldwide health concern, particularly in breastfed infants. This paper reviews the current status of the use of vitamin K for the prevention of early and late VKDB.