Vitamin K for the Prevention of Bleeding in Newborns

Marcia L. Buck, PharmD, FCCP

Pediatr Pharm. 2001;7(10) 

In This Article

Rationale for Current Practice

At birth, all neonates are vitamin K deficient because of limited transfer across the placenta. Serum vitamin K concentrations in newborns are only 30 to 60% of those in adults, but steadily rise within the first weeks of life. While often having undetectable levels at birth, most healthy, breastfed infants will achieve serum concentrations close to an average adult value of 0.4 ng/ml within six weeks. Infants fed with standard vitamin-fortified formulas have much higher vitamin K concentrations, often as much as 10 fold higher, within days after birth.

Administration of vitamin K in the immediate postnatal period provides a rapid increase in serum concentrations and vitamin K-dependent clotting factors. While administration of a single dose by any route appears to be adequate for the prevention of classic VKDB, the current standard of practice in the United States is to give as phytonadione, a lipid-soluble synthetic vitamin K1 analog (AquaMEPHYTON®; Merck), by the intramuscular (IM) route. IM administration produces very high vitamin K concentrations initially, with a gradual decline over several months, providing protection against the development of late VKDB. When compared at 4 weeks of age, infants given IM vitamin K were found to have serum concentrations 1.5 times greater than breastfed infants given no prophylaxis.[1]

With the rarity of VKDB, demonstrating a statistically significant reduction in incidence has been difficult; however, two studies have documented a significant decrease in the incidence of neonatal bleeding.[7,8] Several other clinical trials have demonstrated the efficacy of IM vitamin K by secondary endpoints, such as increasing prothrombin index and reducing serum concentrations of nonfunctional clotting factor precursors, also referred to as proteins induced in vitamin K absence (PIVKA).[9,10,11]


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