Abstract

A randomised clinical trial was conducted to establish the effects of oral and intramuscular administration of vitamin K at birth on plasma concentrations of vitamin K1, proteins induced by vitamin K absence (PIVKA-II), and clotting factors. Two groups of about 165 healthy breast fed infants who received at random 1 mg vitamin K1 orally or intramuscularly after birth were studied at 2 weeks and 1 and 3 months of age. Although vitamin K1 concentrations were statistically significantly higher in the intramuscular group, blood coagulability, activities of factors VII and X and PIVKA-II concentrations did not reveal any difference between the two groups. At 2 weeks of age vitamin K1 concentrations were raised compared with reported unsupplemented concentrations and no PIVKA-II was detectable. At 3 months vitamin K1 concentrations were back at unsupplemented values and PIVKA-II was detectable in 11.5% of infants. Therefore, a repeated oral prophylaxis will be necessary to completely prevent (biochemical) vitamin K deficiency beyond the age of 1 month.