Relationship of milk intake and vitamin K supplementation to vitamin K status in newborns.

Vitamin K status was evaluated by measuring blood acarboxyprothrombin (PIVKA-II) levels on the fifth day of life. The incidence of PIVKA-II-positive infants was higher in breast-fed babies than in those given supplementary (mixed) feeding. The median of total amount of milk intake during the first 3 days was significantly lower in PIVKA-II-positive infants than in PIVKA-II-negative infants among infants given both types of feedings. In addition, there was a significant negative correlation between a positive PIVKA-II proportion and the amount of milk intake in the breast-fed babies. The minimum dose of vitamin K2 necessary to prevent a positive PIVKA-II reading was 15 micrograms among babies with a normal absorption potential.