[General vitamin K prevention in newborn infants].

Vitamin K is required for the synthesis of active forms of some coagulation factors. Bleeding due to low levels of the vitamin K dependent coagulation factors (classic hemorrhagic disease of the newborn) is most frequently seen in newborns with a low intake of breast milk, who are not fed supplemental formula, since transplacental transfer of vitamin K seems to be small and breast milk is relatively deficient in vitamin K. Severe bleeding due to vitamin K deficiency is also observed in 4-12 weeks old infants. The reason for the deficiency in otherwise healthy infants of this age is unclear. Classic hemorrhagic disease of the newborn is not existent in infants given vitamin K intramuscularly at birth. Also, the late manifestation of vitamin K deficiency has been observed virtually exclusively in infants, who had not been given vitamin K parenterally at birth. Since most newborns will be breast fed and supplemental formula feeding will not be required in most healthy full term newborns, all newborns should be given a dose of vitamin K intramuscularly immediately after birth. Whether it is safe to administer vitamin K to the mother or orally to the child requires further investigation.