Birth Dose Vitamin K for Newborns
All newborns should receive a single intramuscular dose of 0.5 to 1.0 mg vitamin K1 within one hour of birth, as this is the most effective and reliable method to prevent all forms of vitamin K deficiency bleeding. 1, 2
Standard Prophylaxis for Term Newborns
The intramuscular route is the gold standard because it provides superior protection against early, classic, and late vitamin K deficiency bleeding (VKDB) compared to oral administration. 1, 3
The dose must be administered within the first hour after delivery to ensure optimal protection. 1, 2
The American Academy of Pediatrics, FDA labeling, and multiple international guidelines consistently recommend the 0.5-1.0 mg IM dose as the primary prophylaxis strategy. 1, 2, 4, 5
Alternative Oral Regimens (When Parents Refuse IM)
If parents decline intramuscular administration after adequate counseling about increased bleeding risk, two oral regimens are acceptable but less effective: 1, 3
Option 1: 2 mg at birth, 2 mg at 4-6 days, and 2 mg at 4-6 weeks 1, 3
Option 2: 2 mg at birth, then weekly 1 mg doses for 3 months (12 weeks total) 1, 3
Parents must understand that oral prophylaxis carries higher failure rates for preventing late VKDB, and compliance with the multi-dose schedule is critical. 3, 4
If the infant vomits or regurgitates within 1 hour of oral administration, the dose should be repeated. 3
Preterm Infants
Preterm infants require different management: 1, 6
Birth prophylaxis: 0.5-1.0 mg IM within one hour of delivery (same as term infants) 1, 6
Ongoing parenteral nutrition: 10 μg/kg/day vitamin K1 continuously while on PN, which is separate from and in addition to the birth dose 7, 1, 6
The oral route is inappropriate for preterm infants due to unreliable absorption and higher bleeding risk. 3
Contraindications to Oral Route
The oral route must not be used in: 3
- Preterm infants
- Infants with cholestasis or impaired intestinal absorption
- Infants too unwell to take oral medications
- Infants whose mothers took medications interfering with vitamin K metabolism (anticonvulsants, anticoagulants, antituberculosis drugs)
High-Risk Newborns
For infants at elevated risk (premature, birth asphyxia, difficult delivery, neonatal disease, maternal anticoagulant use), the initial dose must be given IM or slow IV, and repeated doses may be necessary based on coagulation monitoring. 1, 8
Critical Pitfalls to Avoid
Never use adult multivitamin formulations containing propylene glycol or polysorbate in infants due to toxicity risk. 6
Document parental refusal of IM vitamin K in the medical record, as this creates significant medicolegal risk if late VKDB occurs. 3
Verify vitamin K content of any parenteral multivitamin preparation used in preterm infants, as some formulations lack vitamin K entirely. 6
Exclusively breastfed infants are at particularly high risk because breast milk contains very low vitamin K concentrations, making prophylaxis even more critical. 9, 3
Monitoring and Diagnosis
A prompt shortening of prothrombin time within 2-4 hours after vitamin K administration is diagnostic of VKDB. 1, 9
PIVKA-II (undercarboxylated vitamin K-dependent proteins) is the preferred biomarker for at-risk patients when available, though routine monitoring is not recommended for healthy term infants. 1, 9