With methods available today for the accurate diagnosis of other factor deficiency states and immune thrombocytopenias, VKDB can be distinguished from other disorders by exclusion.
Newborns are relatively vitamin K deficient for a variety of reasons.
Factors that can contribute to this deficiency include low vitamin K stores at birth, poor placental transfer of vitamin K, low levels of vitamin K in breast milk, and sterility of the gut. Because standard commercial infant formulas contain supplemental vitamin K, VKDB almost exclusively is a problem of breastfed infants. Infants with inadequate intake are at higher risk. The most common sites of bleeding are the umbilicus, mucous membranes, GI tract, circumcision, and venipunctures. Hematomas at sites of trauma, such as large cephalohematomas and bruising, also are common findings.