Vitamin K at birth

摘要

That all newborn infants are deficient in vitamin K is apparent from their low plasma concentrations of vitamin K and a deficiency of the vitamin K dependent coagulation factors Ⅱ, Ⅶ, Ⅸ, and Ⅹ. This deficiency results in (early) haemorrhagic disease of the newborn in 0.4%-1.7% of babies in the first week of life. Late haemorrhagic disease occurs almost exclusively in breast fed infants, from 2 to 12 weeks of age, who did not receive intramuscular vitamin K at birth. The incidence has been reported to vary from 4.4 to 10.5 per 100 000 births.