Vitamin K Dosing for a 920g Preterm Infant
For a 920g preterm infant on parenteral nutrition, administer 10 μg/kg/day of vitamin K, which equals approximately 9.2 μg (0.0092 mg) daily. 1, 2, 3
Dosing Calculation and Administration
The weight-based dose is 10 μg/kg/day for preterm infants receiving parenteral nutrition, which for a 920g infant equals 9.2 μg daily 1, 2, 3
This parenteral nutrition dose differs substantially from the prophylactic birth dose and should be given continuously while the infant remains on PN 1
Vitamin K should be administered with lipid emulsions whenever possible to improve stability and reduce vitamin losses 1, 4
Birth Prophylaxis vs. Ongoing PN Requirements
At birth, this infant should have received an initial intramuscular dose of 0.5-1.0 mg (500-1000 μg) within one hour of delivery to prevent vitamin K deficiency bleeding 2, 5
The ongoing daily PN dose of 10 μg/kg/day is separate from and in addition to the birth prophylaxis dose 1, 2
For high-risk preterm infants like this 920g baby, the initial birth dose must be given IM or slow IV route, not orally 2, 6
Critical Considerations for This Weight Category
Preterm infants below 1500g have less adaptive capacity to vitamin variations and require careful weight-based dosing 1
Some multivitamin preparations (like Cernevit™) do not contain vitamin K, which is particularly problematic for premature infants—verify the vitamin K content of any parenteral multivitamin formulation used 1
Adult multivitamin formulations containing propylene glycol and polysorbate must never be used in infants due to toxicity risk 4
Monitoring and Safety
Classical coagulation tests (PT, PTT) can be used for indirect evaluation but are not specific to vitamin K deficiency 1, 3
PIVKA-II (undercarboxylated vitamin K-dependent proteins) is the preferred biomarker for at-risk preterm infants when locally available 1, 3
Doses may need to be repeated, particularly in premature infants, with the route of administration decided according to the clinical state 6
Common Pitfalls to Avoid
Do not confuse the birth prophylaxis dose (0.5-1.0 mg IM once) with the daily PN maintenance dose (10 μg/kg/day) 1, 2, 5
Oral vitamin K is not appropriate for preterm infants or those on parenteral nutrition 7, 8
Risk factors requiring vigilance include cholestasis, biliary atresia, cystic fibrosis, and maternal medications interfering with vitamin K metabolism 1, 3