Vitamin K in Prenatal Prevention and Postnatal Treatment of Haemorrhagic Disease of the Newborn.

Vitamin K is an essential in human nutrition for the maintenance of normal blood clotting function. It is involved in the synthesis of prothrombin and is directly related to the concentration of the latter in the circulating blood. We have (Kugelmass and Samuel, 1931) advanced the hypothesis of a dietary basis of the formation of clotting constituents, formulated 'clotting' and 'bleeding' diets (Kugelmass, 1935a), and applied these in the treatment of amenable haemorrhagic diseases (Kugelmass, 1934). The isolation of the poultry-feed factor in crystalline form (Dam and Lewis, 1937) as vitamin K by Almquist (1937) has led us to determine its effectiveness in haemorrhagic disease of the newborn characterized by diminution in blood prothrombin. This anti-haemorrhagic vitamin is a complex of K1 derived from vegetable and K2 derived from animal sources. The potency of each of these compounds has been determined by various methods of assay (Thayer et al., 1939). These data indicate that vitamin K1 is approximately twice as potent as,K2, the former about 1000 units per mgm. and the latter about 660 units. A unit of vitamin K is defined as that quantity which produces a clotting time of ten minutes or less in half a group of ten or more chicks which have been fed for two weeks immediately following a vitamin K-free dietary.