- Clinical science
Vitamin K deficiency bleeding of the newborn (VKDB) refers to spontaneous bleeding in a newborn caused by a deficiency of vitamin K dependent coagulation factors. As vitamin K does not cross the placental barrier, is not present in breast milk, and is not synthesized in the sterile gut of a newborn, vitamin K levels are low in all neonates. VKDB is rare in industrialized countries as most children receive a vitamin K injection at birth. VKDB is categorized as early-onset (within 24 hours after birth), classic (within 4 weeks), or late-onset (between 2–8 months). Common sites of bleeding include intracranial, subgaleal, gastrointestinal, and nasal. Treatment is focused on managing the bleeding with, e.g., transfusions and restoring bleeding homeostasis by administering vitamin K.
- Without prophylaxis: affects 0.25–2% of newborns
Epidemiological data refers to the US, unless otherwise specified.
The underlying cause is always a deficiency of vitamin K, which can be due to various factors:
- Exclusive breastfeeding: low vitamin K levels in breast milk (most important in late-onset VKDB)
- Low liver storage capacity
- Poor placental passage of vitamin K
- Vitamin K deficiency in the mother (e.g., because of therapy; most important in early-onset VKDB; maternal malnutrition)
- Underdeveloped intestinal flora (which produces vitamin K), e.g., due to premature birth
- Chronic diarrhea of the newborn
- Long-term antibiotic treatment in newborns
- Cholestatic diseases (e.g., biliary atresia)