Vitamin K in the newborn: influence of nutritional factors on acarboxy-prothrombin detectability and factor II and VII clotting activity

Prevention of Vitamin K Deficiency Bleeding in Newborn Infants: A Position Paper by the ESPGHAN Committee on Nutrition

Vitamin K deficiency bleeding (VKDB) due to physiologically low vitamin K plasma concentrations is a serious risk for newborn and young infants and can be largely prevented by adequate vitamin K supplementation. The aim of this position paper is to define the condition, describe the prevalence, discuss current prophylaxis practices and outcomes, and to provide recommendations for the prevention of VKDB in healthy term newborns and infants. All newborn infants should receive vitamin K prophylaxis and the date, dose, and mode of administration should be documented. Parental refusal of vitamin K prophylaxis after adequate information is provided should be recorded especially because of the risk of late VKDB. Healthy newborn infants should either receive 1 mg of vitamin K1 by intramuscular injection at birth; or 3 × 2 mg vitamin K1 orally at birth, at 4 to 6 days and at 4 to 6 weeks; or 2 mg vitamin K1 orally at birth, and a weekly dose of 1 mg orally for 3 months. Intramuscular application is the preferred route for efficiency and reliability of administration. The success of an oral policy depends on compliance with the protocol and this may vary between populations and healthcare settings. If the infant vomits or regurgitates the formulation within 1 hour of administration, repeating the oral dose may be appropriate. The oral route is not appropriate for preterm infants and for newborns who have cholestasis or impaired intestinal absorption or are too unwell to take oral vitamin K1, or those whose mothers have taken medications that interfere with vitamin K metabolism. Parents who receive prenatal education about the importance of vitamin K prophylaxis may be more likely to comply with local procedures.

Vitamin K deficiency bleeding (VKDB) in early infancy

Vitamin K deficiency bleeding (VKDB) is a rare and potentially life-threatening bleeding disorder of early infancy. Vitamin K stores are low at birth; thereafter breast-fed infants are at risk because of low concentrations in human milk. Classical VKDB occurs in the first week of life, is related to delayed or inadequate feeding and is readily prevented by small doses of vitamin K at birth. Late VKDB peaks at 3-8 weeks, typically presents with intracranial haemorrhage often due to undiagnosed cholestasis with resultant malabsorption of vitamin K. Diagnosis can be difficult but PIVKA-II measurements can provide confirmation even several days post-treatment. Without vitamin K prophylaxis, the incidence of late VKDB in Europe is 4-7 cases per 10(5) births; it is higher in SE Asia where in rural, low-income areas some 0.1% of affected infants may suffer intracranial bleeding. Late VKDB is largely preventable with parenteral vitamin K providing the best protection. The efficacy of oral prophylaxis is related to the dose and frequency of administration. Most multi-dose oral regimens provide protection for all except a small reservoir of infants with undetected hepatobiliary disease. Targeted surveillance of high-risk groups (e.g. biliary atresia) offers a novel approach to assess efficacy of prophylaxis.

Plasma vitamin K1 and PIVKA-II after oral administration of mixed-micellar or cremophor EL-solubilized preparations of vitamin K1 to normal breast-fed newborns

BACKGROUND

Vitamin K1 prophylaxis in neonates is required for prevention of vitamin K1 deficiency bleeding. Although intramuscular administration of vitamin K1 is safe, this invasive method is not generally accepted. We therefore examined the pharmacokinetics of two orally administered vitamin K1 preparations in normal, fully breast-fed newborns.

METHODS

Within 1 hour of birth, each baby was randomized to a 2 mg dose of either a conventional Cremophor EL-solubilized preparation of vitamin K1 (Konakion drops, F. Hoffmann-La Roche, n = 16), or a new mixed-micellar preparation of vitamin K1 (Konakion MM, F. Hoffmann-La Roche, n = 14). The concentrations of vitamin K1, des-gamma-carboxyprothrombin (PIVKA-II), and total bound bilirubin were measured in plasma samples taken at 24 hours, 4 days, and 24 days after birth.

RESULTS

The median concentration of plasma vitamin K1 was higher at all three time points in the group that received the mixed-micellar preparation, but the difference was only significant (p < 0.05) at 4 days. At 24 hours and 4 days, PIVKA-II was detectable in a significantly lower proportions of infants receiving the new mixed-micellar preparation than those receiving the Cremophor EL preparation (21% vs. 75% at 24 hours, p < 0.05 and 14% vs. 50% at 4 days, p < 0.05). None of the infants in the study had detectable PIVKA-II levels 24 days after birth.

CONCLUSIONS

Our results suggest that when given orally, the mixed-micellar preparation is superior to the conventional formulation because it increases plasma vitamin K1 concentrations to higher levels, suggesting superior bioavailability, and decreases PIVKA-II concentrations more efficiently, suggesting a faster pharmacodynamic response.

Relationship between vitamin K dependent coagulation factors and anticoagulants (protein C and protein S) in neonatal vitamin K deficiency

To determine the relationship between vitamin K dependent coagulation factors and natural anticoagulants, namely protein C and protein S, in various degrees of vitamin K deficiency, plasma values for clotting activity, protein induced by vitamin K absence (PIVKA-II), protein C antigen, gamma-carboxy protein C antigen, and protein S antigen including total and free fractions and activity of protein C were measured in 66 full term and healthy breast fed neonates who did not receive vitamin K supplement at birth. The 66 neonates were divided into a control group (17 cases) and a low group (49 cases) according to their values for clotting activity--that is, > or = 20% or < 20% during the first six days of life--and vitamin K was immediately given when the neonates showed values < 20%. In the low group clotting activity gamma-carboxy protein C, free protein S, and protein C activity was significantly decreased to a minimum on day 2 or 3, and increased in parallel after vitamin K administration. Furthermore, they were positively correlated with one another and inversely cor-correlated with the PIVKA-II concentrations. These findings suggest that simultaneous gamma-carboxylation of coagulation factors and proteins C and S acts to maintain both coagulation and anticoagulation activities in parallel at various concentrations of vitamin K. The breast milk intake in the group with low values of clotting activity was significantly lower than that in the control group during the first three days of life.(ABSTRACT TRUNCATED AT 250 WORDS)

Vitamin K metabolism and nutriture

Vitamin K functions as a co-factor for the post-translational carboxylation of specific glutamate residues to gamma-carboxyglutamate (Gla) residues in several blood coagulation factors (II, VII, IX and X) and coagulation inhibitors (proteins C and S) in the liver; as well as a variety of extrahepatic proteins such as the bone protein osteocalcin. This review outlines some recent advances in our understanding of the metabolism of vitamin K and its role in human nutriture. The introduction of new methodologies to measure the low endogenous tissue concentrations of K vitamins and circulating plasma levels of des-gamma-carboxyprothrombin (PIVKA-II) have provided correspondingly more refined indices for the assessment of human vitamin K status. The assays for vitamin K have also been used to study the sources, intestinal absorption, plasma transport, storage and transplacental transfer of K vitamins and the importance of phylloquinone (vitamin K1) versus menaquinones (vitamins K2) to human needs. The ability to biochemically monitor subclinical vitamin K deficiency has reaffirmed the precarious vitamin K status of the newborn and led to an increased appreciation of the risk factors leading to haemorrhagic disease of the newborn and how this may be prevented. Biochemical studies are leading to an increased knowledge of the mode of action of traditional coumarin anticoagulants and how some unrelated compounds (e.g. antibiotics) may also antagonize vitamin K and cause bleeding. There is also an awareness of the possible deleterious effects of vitamin K antagonism or deficiency on non-hepatic Gla-proteins which may play some subtle role in calcium homeostasis.

Vitamin K in infancy

Vitamin K has regained paediatric interest due to a recurrence of bleeding caused by deficiency of the vitamin in newborns and young infants. Increasing awareness of these clinical problems, the development of new methods for the detection of vitamin K deficiency and the direct measurement of vitamin K in tissues have stimulated research. Much new data obtained from these studies has proved helpful to the understanding of vitamin K deficiency in infancy. For example low concentrations of vitamin K have been found in fetal and neonatal livers. The implications of these findings with respect to manifest vitamin K deficiency and to new methods for detection of subclinical vitamin K deficiency are discussed. Breast-feeding is a major risk factor for classical haemorrhagic disease of the newborn and for late onset bleeding due to vitamin K deficiency in young infants. The interdependencies between breast-feeding and vitamin K deficiency are discussed on the basis of new data obtained from direct measurement of vitamin K in maternal milk. The review further focuses on pathophysiological concepts of bleeding due to vitamin K deficiency in infancy and current concepts of vitamin K prophylaxis.