Classic vitamin K deficiency bleeding usually occurs after 24 hours and as late as the first week of life. Classic vitamin K deficiency bleeding is observed in infants who have not received prophylactic vitamin K at birth.
The incidence of classic vitamin K deficiency bleeding ranges from 0.25-1.7 cases per 100 births.
Usually the disease occurs from the second day of life to the end of the first week; however, it can occur during first month and sometimes overlaps with late-onset vitamin K deficiency bleeding.
Infants who have classic vitamin K deficiency bleeding are often ill, have delayed feeding, or both. Bleeding commonly occurs in the umbilicus, GI tract (ie, melena), skin, nose, surgical sites (ie, circumcision), and, uncommonly, in the brain