Which of these is a feature of hemorrhagic disease of new born?

Normal newborns are moderately deficient in vitamin K. This deficiency increases on 3rd to 5th day when, vitamin K level falls fuher. The serum level of vitamin K stas increasing from 13th to 15th day of life and achieves adult level at 3 months. In hemorrhagic disease of the newborn, there is delay in achieving the normal vitamin K level. Prolongation of PT values is the most common and earliest finding in vitamin K-deficient patients due to reduction in prothrombin, factor VII, IX, and X levels. F VII has the shoest half-life among these factors that can prolong the PT before changes in the aPTT.