Changes Brought about in Blood Coagulation in the Newborn by Adminstration of Vitamin K2

Deficiency of the blood coagulation factor, especially of vitamin K-dependent factors, is a major disturbance of extrauterine life in the neonatal period. It is well known that vitamin K1 is converted to vitamin K2 in the human body. In order to compare the effectiveness of vitamin K1 and that of vitamin K2 in the newborn period, changes in coagulability were studied not only at the end of the day after birth but also along the time course. Six hrs after birth, 2 mg of vitamin K1 or vitamin K2 was injected intramuscularly into the thigh of the newborn, and the effects were observed by thrombotest and normotest 3, 15, and 24 hrs after injection. In this experiment, the infants treated with vitamin K2 showed higher values in the thrombotest than those treated with vitamin K1 after 3 and 15 hrs. After 24hrs however, there was no longer any significant difference between the K1 and K2 groups. As a clinical application of vitamin K2, gastrointestinal bleeding was studied polarographically with the emulsion of meconium or stool. Since the origin of vitamin K2 is the gastrointestinal bacterial flora, changes in the occult blood were studied in one group given 2 mg of vitamin K2 and mixed milk (18 cases), a second group given 2 mg of vitamin K1 and mixed milk (21 cases), and a control group (24 cases). Haemoglobin percentage of newbornfaces are greatly diminished by a oral adminstration of vitamin K2. Both results may indicate rapid action of vitamin K2.