Vitamin K Deficiency Bleeding of the Newborn

Vitamin K deficiency bleeding is a potentially serious bleeding disorder affecting newborns and young infants. It results from physiologically low vitamin K stores at birth combined with the relative immaturity of the neonatal coagulation system.

Onset is classified by timing:

• Early: within twenty-four hours of birth, generally associated with maternal medication exposure.
• Classical: day one to seven of life.
• Late: two to twelve weeks, occasionally up to six months, of age, carrying particular risk of intracranial haemorrhage.

Routine prophylactic vitamin K administration at birth is one of the most effective, well established preventive interventions in neonatal care. It has dramatically reduced incidence through this simple, low-risk measure.

Pathophysiology and risk factors

• Vitamin K is essential for hepatic synthesis of the functional forms of clotting factors II, VII, IX, and X, together with proteins C and S. Newborns are physiologically vulnerable to deficiency given poor placental transfer of maternal vitamin K, low vitamin K content in breast milk, and immature neonatal hepatic synthetic function.
• Without prophylaxis, a meaningful proportion of infants pass through a period of genuinely inadequate vitamin K-dependent clotting factor activity.
• Exclusively breastfed infants who have not received prophylaxis carry substantially higher risk than formula-fed infants, given the comparatively low vitamin K content of breast milk relative to the routinely fortified content of infant formula.
• Maternal use of medications that interfere with vitamin K metabolism, including certain antiepileptic drugs, warfarin, and rifampicin, increases the risk of early-onset disease specifically. This follows placental transfer of these agents and their direct effect on the infant's already limited vitamin K stores.
• Late-onset disease is particularly associated with conditions producing malabsorption or reduced vitamin K intake beyond the immediate newborn period, including cholestatic liver disease, cystic fibrosis, and coeliac disease. Exclusive breastfeeding without adequate prophylaxis is also associated. Vitamin K sufficiency remains relevant beyond the immediate perinatal period.

• Early-onset disease presents within the first twenty-four hours of life, often with severe bleeding including intracranial or intra-abdominal haemorrhage, reflecting the combined effect of significant maternal medication exposure and inadequate fetal vitamin K stores.
• Classical disease presents between day one and seven of life with bleeding from the umbilical stump, gastrointestinal tract, or following circumcision or other minor procedural trauma, together with generalised bruising, generally milder in severity than the early-onset pattern.
• Late-onset disease presents between two weeks and several months of age, characteristically in an exclusively breastfed infant who has not received adequate prophylaxis. It has a particularly concerning association with intracranial haemorrhage, which can present with non-specific features including irritability, lethargy, poor feeding, or seizures, together with, in some cases, a bulging fontanelle.
• This warrants a high index of suspicion in any unwell infant within this specific age range and risk context.
• Any unexplained bleeding or bruising in a young infant, particularly one who has not received vitamin K prophylaxis at birth, warrants urgent evaluation for this diagnosis given the potential severity and time-critical nature of appropriate treatment.

• Diagnosis is supported by a markedly prolonged prothrombin time with a normal or near-normal fibrinogen and platelet count, reflecting the specific pattern of vitamin K-dependent clotting factor deficiency rather than a broader coagulopathy or thrombocytopenic process.
• A clinical response to administration of vitamin K, with correction of the prolonged prothrombin time within hours, provides further supportive confirmation of the diagnosis.
• Careful review of the infant's vitamin K prophylaxis status at birth, together with feeding history and any relevant maternal medication exposure, forms an essential component of diagnostic evaluation.
• Neuroimaging is indicated where intracranial haemorrhage is suspected based on the clinical presentation, given the direct relevance to both diagnosis confirmation and subsequent management planning.

• Universal prophylactic vitamin K administration at birth is the essential, standard preventive measure recommended for every newborn infant regardless of feeding method.
• It is given either as a single intramuscular injection (providing the most reliable, sustained protection, including against the specific, important late-onset disease pattern) or as a multi-dose oral regimen (requiring reliable completion of the full course to achieve comparable protection).
• This simple, low-risk intervention has dramatically reduced incidence.
• Acute bleeding is managed with immediate intravenous vitamin K administration, together with fresh frozen plasma or prothrombin complex concentrate for significant, active haemorrhage, delivered as an urgent intervention given the potential severity of associated bleeding, particularly intracranial haemorrhage.
• Full supportive care, including management of any identified intracranial haemorrhage according to standard principles, together with careful, ongoing monitoring of coagulation status until full correction is confirmed, underpins full acute management.
• Clear, sensitive discussion is needed with parents who decline prophylactic vitamin K administration at birth. Provide accurate, balanced information regarding the specific risks of deficiency bleeding and the excellent safety profile of prophylaxis, together with a low threshold for reassessment should any concerning symptom subsequently develop, represents an important, ongoing component of full newborn care.