Epidemiology

Etiology

• Exclusive breastfeeding: low vitamin K levels in breast milk (most important in late-onset VKDB)
• Vitamin K deficiency in the mother (e.g., because of anticonvulsant therapy; most important in early-onset VKDB; maternal malnutrition)
• Underdeveloped intestinal flora (which produces vitamin K), e.g., due to premature birth
• Long-term antibiotic treatment in newborns

Classification

• Early onset: within 24 hours after birth; intracranial bleeding common
• Classic: within 1 week after birth; intracranial bleeding rare
• Late onset: between 2–8 months after birth; intracranial bleeding common

Pathophysiology

Clinical features

• Classically presents on day 2-7 of life
• Easy bruising
• Umbilical, mucosal & gastrointestinal bleeding
• Intracranial hemorrhage

Diagnostics

Treatment

In the US, all newborns receive intramuscular vitamin K (0.5–1 mg) at birth.