The term hemorrhagic disorder of the newborn encompasses all hemorrhagic diseases, i.e., due to vitamin K deficiency, trauma, clotting factor deficiency, etc. When the cause is vitamin K deficiency, it is referred to as vitamin K deficiency bleeding or VKDB.
There is a very limited transplacental transfer of vitamin K from mother to fetus in utero consequently there is very little storage of vitamin K in neonatal liver making a neonate vulnerable for development of vitamin K deficiency.
VKDB in infancy is classified according to the time of presentation: early (within 24 h), classic (within 1 week after birth), and late (between 2 week and 6 months of age). VKDB in infancy, particularly late-onset VKDB, can be life-threatening.
Early and classical VKDB are more common, occurring in 1 in 60 to 1 in 250 newborns, although the risk is much higher for early VKDB among those infants whose mothers used certain medications during the pregnancy.
Vitamin K is a fat-soluble vitamin that occurs in 2 forms- vitamin K1 or phylloquinone (present in green leafy vegetables) and vitamin K2 or menaquinone (synthesized by the gram-negative bacteria in the intestines). Although vitamin K has many other roles in the body, its major role involves the activation of clotting factors. It is a necessary cofactor for the synthesis and activation of coagulation factors II (prothrombin), VII, IX, and X (vitamin K-dependent coagulation factors) and proteins C and S in the liver.
Hemorrhagic disease of the newborn
