What is the rationale for administering vitamin K (phylloquinone) to newborns?

Rationale for Vitamin K Administration to Newborns

Vitamin K is administered to newborns primarily to prevent hemorrhagic disease of the newborn (now called vitamin K deficiency bleeding or VKDB), as newborns have physiologically low vitamin K-dependent coagulation factors that put them at risk for potentially life-threatening bleeding. 1

Why Newborns Need Vitamin K Supplementation

• Newborns have physiologically decreased plasma levels of vitamin K-dependent coagulation factors (factors II, VII, IX, and X) compared to adults, making them vulnerable to bleeding disorders 2
• Breast milk contains low concentrations of vitamin K, making exclusively breastfed infants particularly susceptible to vitamin K deficiency 2, 3
• Without prophylaxis, newborns are at risk for three forms of vitamin K deficiency bleeding: early, classic, and late VKDB 4
• The American Academy of Pediatrics recommends vitamin K administration to all newborns to prevent this potentially fatal condition 5

Risk Factors for Vitamin K Deficiency in Newborns

• Exclusive breastfeeding (breast milk contains insufficient vitamin K) 3
• Maternal medications that interfere with vitamin K metabolism (anticonvulsants, anticoagulants, antituberculosis drugs) 3, 4
• Underlying conditions such as cystic fibrosis, alpha-1-antitrypsin deficiency, or cholestasis 3
• Preterm birth, which further decreases vitamin K-dependent factors 4
• Birth trauma or difficult delivery that may increase bleeding risk 4

Recommended Administration Protocol

• The preferred method is a single intramuscular injection of 0.5 to 1.0 mg vitamin K1 (phytonadione) within one hour of birth 5, 6
• Alternative oral regimens for parents who decline IM administration:
  • 3 × 2 mg vitamin K1 orally at birth, at 4-6 days, and at 4-6 weeks; OR
  • 2 mg vitamin K1 orally at birth, followed by weekly doses of 1 mg for 3 months 1
• For high-risk infants (premature, birth asphyxia, difficult delivery, delayed feeding, hepatic disease), intramuscular or slow intravenous administration is strongly recommended 4

Efficacy of Different Administration Routes

• Intramuscular administration is the most effective method for preventing all forms of VKDB 6, 7
• Single oral doses effectively prevent early and classic VKDB but are less effective against late VKDB compared to IM administration 4, 8
• Multiple oral doses can be effective but require strict adherence to the dosing schedule, which may vary between populations and healthcare settings 1

Safety Considerations

• The previously reported association between intramuscular vitamin K administration and childhood cancer has not been substantiated by subsequent research 8
• Vitamin K1 (phylloquinone) is considered safe with no known adverse effects of supplementation 2
• For preterm infants on parenteral nutrition, a dose of 10 μg/kg/day of vitamin K is recommended 3, 9

Special Considerations

• If an infant vomits or regurgitates oral vitamin K within 1 hour of administration, repeating the dose may be appropriate 1
• The oral route is not appropriate for preterm infants, infants with cholestasis, impaired intestinal absorption, or those too unwell to take oral vitamin K1 1
• Parental education about the importance of vitamin K prophylaxis increases compliance with local protocols 1
• Documentation of vitamin K administration (date, dose, and route) is essential for all newborns 1