What are the current recommendations for vitamin K (Vitamin K1, phylloquinone) administration to neonates?

Vitamin K Administration in Neonates

All newborns should receive vitamin K prophylaxis at birth, with a single intramuscular dose of 0.5 to 1.0 mg vitamin K1 (phylloquinone) administered within one hour of birth being the gold standard for preventing vitamin K deficiency bleeding (VKDB). 1, 2

Rationale for Universal Prophylaxis

• Newborns have physiologically low plasma levels of vitamin K-dependent coagulation factors (II, VII, IX, and X), making them vulnerable to potentially fatal bleeding disorders 3
• Placental transfer of vitamin K is limited, and breast milk contains very low concentrations of vitamin K, placing exclusively breastfed infants at particularly high risk 3, 4
• Without prophylaxis, VKDB can occur in three forms: early (first 24 hours), classic (days 2-7), and late (2-12 weeks), with late VKDB being especially dangerous as it often presents with intracranial hemorrhage 5

Recommended Administration Routes and Dosing

Intramuscular Route (Preferred)

The intramuscular route is strongly preferred because it is the most effective and reliable method for preventing all forms of VKDB, including late VKDB. 5, 6

• Dose: 0.5 to 1.0 mg vitamin K1 given as a single intramuscular injection within one hour of birth 1, 2, 6
• Efficacy: Single IM administration at birth effectively prevents classic, early, and late VKDB 4, 5
• The IM route ensures reliable absorption and does not depend on parental compliance with follow-up dosing 5

Oral Route (Alternative Only When IM Declined)

Oral administration should only be used when parents decline intramuscular vitamin K, and parents must be clearly informed that their infant remains at increased risk of VKDB with this approach. 6, 7

If oral route is chosen, use one of these evidence-based regimens:

• Option 1: 2 mg at birth, repeated at 2-4 days and again at 4-6 weeks 5
• Option 2: 2 mg at birth, then weekly doses of 1 mg for 3 months 5
• Option 3: 3 doses of 2 mg each at birth, 4-6 days, and 4-6 weeks 5

Critical caveat: Single oral doses are insufficient and do not prevent late VKDB 4, 5. If the infant vomits or regurgitates within 1 hour of oral administration, the dose should be repeated 5

Special Populations Requiring IM Administration

The oral route is contraindicated and IM administration is mandatory in the following situations: 5

• Preterm infants (who should receive 10 μg/kg/day if on parenteral nutrition) 3, 1, 8
• Infants with cholestasis or impaired intestinal absorption 5
• Infants too unwell to take oral medications 5
• Infants whose mothers took medications interfering with vitamin K metabolism (anticonvulsants, anticoagulants, antituberculosis drugs) 3, 2
• Infants with underlying diseases such as cystic fibrosis, alpha-1-antitrypsin deficiency, or cholestasis 3

High-Risk Infants Requiring Higher or Repeated Doses

For infants of mothers on oral anticoagulants or other vitamin K-inhibiting drugs, higher doses may be necessary 2. These infants should receive 1 mg IM as soon as possible after birth 4. Consider antenatal maternal prophylaxis (10-20 mg/day orally for 15-30 days before delivery) to prevent early VKDB 9

Administration Technique and Safety

• Administer by subcutaneous or intramuscular route; intravenous administration should be avoided when possible 2
• If IV administration is unavoidable, inject very slowly, not exceeding 1 mg per minute 2
• Protect vitamin K from light at all times 2
• Benzyl alcohol-containing diluents should not be used in newborns due to toxicity risk 2
• Vitamin K1 (phylloquinone) is considered safe with no known adverse effects from supplementation 3

Documentation and Parental Counseling

• Document the date, dose, and route of administration in the medical record 5
• If parents refuse vitamin K prophylaxis after adequate counseling, this refusal must be documented due to the serious risk of late VKDB 5
• Parents who receive prenatal education about vitamin K prophylaxis are more likely to comply with recommendations 5

Monitoring Considerations

• Routine monitoring of vitamin K concentrations is not recommended 10
• Classical coagulation tests (PT, PTT) can be used for indirect evaluation but are not specific to vitamin K deficiency 3, 8
• PIVKA-II (undercarboxylated vitamin K-dependent proteins) is a more useful biomarker for at-risk patients when locally available 3, 8
• A prompt response (shortening of prothrombin time within 2-4 hours) following vitamin K administration is diagnostic of VKDB 2

Common Pitfalls to Avoid

• Never rely on a single oral dose - this does not prevent late VKDB 4, 5
• Do not use daily oral doses of 25 μg - this offers insufficient protection 4
• Do not assume formula-fed infants are fully protected - while they have lower risk than breastfed infants, prophylaxis is still recommended for all newborns 5
• Do not forget follow-up doses if oral route is used - the success of oral prophylaxis depends entirely on compliance with the multi-dose regimen 5