Why is vitamin K administered to newborns?

Vitamin K is administered to newborns primarily because they are born with a deficiency of this vitamin. This deficiency arises due to several factors, including the fact that vitamin K does not easily cross the placenta and that newborns have a limited supply of the vitamin stored in their bodies at birth. Additionally, the gut of newborns is sterile at delivery, meaning they lack the bacteria needed to produce vitamin K. As a result, without supplementation, newborns are at an increased risk for bleeding disorders, particularly the potentially serious condition known as "hemorrhagic disease of the newborn."

This preventive measure is crucial as vitamin K plays a vital role in the synthesis of clotting factors that are essential for normal blood coagulation. Administering vitamin K shortly after birth helps ensure that the newborn has adequate levels to prevent bleeding complications in the days and weeks following delivery.