Newborns receive a single injection of vitamin k at birth because newborns receive a single injection of vitamin k at birth because newborns do not have enough mature gi flora to make vitamin k. breast milk is a poor source of vitamin k. the trauma of labor and delivery depletes the newborn's vitamin k stores. newborns cannot absorb any of the vitamin k from breast milk or formula.

Newborns receive a single injection of vitamin K at birth due to the fact that the newborns don't have enough bacteria to make vitamin K.
Vitamin K at birth helps the blood to clot and prevents serious bleeding. In newborns, vitamin K injections can prevent a now rare, but potentially fatal, bleeding disorder called 'vitamin K deficiency bleeding' also known as 'hemorrhagic disease of the newborn'.