Late Vitamin K Deficiency Bleeding in Infancy: The Time to Ensure Effective Prevention.

Recent evidence is discussed that underlies the necessity for broader practice changes regarding vitamin K (VK) supplementation to protect all breastfed infants from the preventable deficiency of this essential micronutrient. Vitamin K deficiency bleeding (VKDB) is characterized by bleeding disorders due to insufficient activity of VK-dependent coagulation factors. Bleeding can range from mild to severe, including life-threatening intracranial hemorrhages. It is widely accepted that to prevent early VKDB, VK prophylaxis should be administered to all newborn infants at birth, typically as an intramuscular (IM) injection or, in some cases, oral supplementation. Both IM and oral administration of VK at birth effectively prevent early VKDB but do not completely protect infants from late VKDB, especially if they are breastfed. Various regimens of both parenteral and oral prophylaxis have been implemented, but insufficient evidence supports any single clinical approach. There is substantial variability in recommendations for VK prophylaxis strategies. Recent, prospective, observational clinical studies of term and preterm infants have revealed that, despite IM administration of VK at birth, exclusively breastfed infants exhibit VK insufficiency after hospital discharge. This insufficiency is particularly pronounced in preterm infants fed breast milk, some of whom demonstrate significantly lower serum VK levels, elevated proteins induced by VK absence or antagonist-II (PIVKA-II) concentrations, and a higher percentage of under-γ-carboxylated osteocalcin compared with those receiving formula feeding. Similarly, term infants breastfed without continued VK supplementation have significantly higher PIVKA-II concentrations than those receiving a daily supplement of 150 μg of VK. This underscores the importance of ongoing VK prophylaxis during the first 3 months of life to effectively prevent late-onset VKDB.