Vitamin K Dosing for Preterm Infants

Dosing Calculation and Administration

The American Academy of Pediatrics recommends a weight-based dose of 10 μg/kg/day of vitamin K for preterm infants receiving parenteral nutrition, which for a 920g infant equals 9.2 μg daily 1, 2, 3
The daily 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

The initial intramuscular dose of 0.5-1.0 mg (500-1000 μg) within one hour of delivery is recommended to prevent vitamin K deficiency bleeding 2
The ongoing daily PN dose of 10 μg/kg/day is separate from and in addition to the birth prophylaxis dose 1, 2

Preterm infants below 1500g have less adaptive capacity to vitamin variations and require careful weight-based dosing 5
Some multivitamin preparations do not contain vitamin K, which is particularly problematic for premature infants—verify the vitamin K content of any parenteral multivitamin formulation used 5
Adult multivitamin formulations containing propylene glycol and polysorbate must never be used in infants due to toxicity risk 4

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
Risk factors requiring vigilance include cholestasis, biliary atresia, cystic fibrosis, and maternal medications interfering with vitamin K metabolism 5, 3