Placental Transfer of Vitamin K1 and Its Implications in Fetal Hemostasis

Range of protein induced by vitamin K absence or antagonist-II levels in neonates at birth

Protein induced by vitamin K absence or antagonist-II (PIVKA-II) is avitamin K (VK) deficiency indicator in neonates. However, PIVKA-II detection frequency in neonatal blood at birth and the correlation between PIVKA-II and gestational age are unclear. We retrospectively analyzed infants admitted to our institution between June 1, 2018, and March 31, 2022, whose clinical and PIVKA-II data were available, and classified them into preterm and term infant groups. Overall incidence of PIVKA-II-positive cases (≥ 50 mAU/mL) was 42.8%, including 0.6% apparent VK deficiency (≥ 5000 mAU/mL), 3.1% experimental VK deficiency (1000-4999 mAU/mL), and 10.7% latent VK deficiency (200-999 mAU/mL) cases. Incidence of PIVKA-II-positive cases was significantly higher in the term group than in the preterm group (49.4% vs. 29.7%, p < 0.001). Gestational age correlated with PIVKA-II levels (r2 = 0.117, p < 0.0001). Median serum PIVKA-II levels and incidence of PIVKA-II-positive cases (≥ 50 mAU/mL, 16.4%) were lower at 5 days after birth than at birth, possibly reflecting the postnatal VK prophylaxis impact. Only one infant was diagnosed with VK deficiency bleeding (PIVKA-II levels, at birth: 10,567 mAU/mL; at day 5: 2418 mAU/mL). Thus, serum PIVKA-II levels after birth weakly correlated with gestational age. VK deficiency was more common in term infants than in preterm infants.

Vitamin K and ECMO for neonatal hypoxic respiratory failure

INTRODUCTION

The objectives of this retrospective cohort study were to examine the effect of vitamin K administration on hemorrhagic and thrombotic complications, blood product utilization, and outcomes in neonatal extracorporeal membrane oxygenation (ECMO).

METHODS

In the pilot study, complications, blood product use, and outcome data for neonates who received (n = 21) or did not receive (n = 18) a single dose of vitamin K (5 mg) immediately after initiation of ECMO for respiratory failure between 2006 and 2010 were compared. In the validation cohort, complications and outcomes were compared for 74 consecutive neonates supported with ECMO for respiratory failure who received (n = 45) or did not receive (n = 29) additional vitamin K once daily for prothrombin time (PT) ⩾14 seconds during ECMO from 2014 to 2019.

RESULTS

In the pilot study, vitamin K at ECMO initiation was associated with fewer thrombotic complications and similar hemorrhagic complications. The volume of fresh frozen plasma was higher in neonates who received vitamin K, but total blood product and other component volume did not differ between groups. ECMO run time, survival off ECMO, survival to discharge, and length of stay did not differ between cohorts. In the validation cohort, neonates who received additional vitamin K during ECMO had longer ECMO run time and length of stay, but no difference in mortality was observed. Further, thrombotic and hemorrhagic complications as well as blood product exposure were similar between cohorts.

CONCLUSIONS

These data suggest that routine vitamin K administration may have limited or no benefit during neonatal ECMO.

Laboratory assessment of vitamin K status

Vitamin K is required for the ɣ-carboxylation of specific glutamic acid residues within the Gla domain of the 17 vitamin K-dependent proteins (VKDPs). The timely detection and correction of vitamin K deficiency can protect against bleeding. Vitamin K also plays a role in bone metabolism and vascular calcification. Patients at increased risk of vitamin K deficiency include those with a restricted diet or malnutrition, lipid malabsorption, cancer, renal disease, neonates and the elderly. Coagulation assays such as the prothrombin time have been used erroneously as indicators of vitamin K status, lacking sufficient sensitivity and specificity for this application. The measurement of phylloquinone (K1) in serum is the most commonly used marker of vitamin K status and reflects abundance of the vitamin. Concentrations <0.15 µg/L are indicative of deficiency. Disadvantages of this approach include exclusion of the other vitamin K homologues and interference from recent dietary intake. The cellular utilisation of vitamin K is determined through measurement of the prevalence of undercarboxylated VKDPs. Most commonly, undercarboxylated prothrombin (Protein Induced by Vitamin K Absence/antagonism, PIVKA-II) is used (reference range 17.4–50.9 mAU/mL (Abbott Architect), providing a retrospective indicator of hepatic vitamin K status. Current clinical applications of PIVKA-II include supporting the diagnosis of vitamin K deficiency bleeding of the newborn, monitoring exposure to vitamin K antagonists, and when used in combination with α-fetoprotein, as a diagnostic marker of hepatocellular carcinoma. Using K1 and PIVKA-II in tandem is an approach that can be used successfully for many patient cohorts, providing insight into both abundance and utilisation of the vitamin.

A rare case of fetal extensive intracranial hemorrhage and whole-cerebral hypoplasia due to latent maternal vitamin K deficiency

We present here a late preterm infant with extensive brain lesions resulting from vitamin K deficiency. A female infant was born after 35 weeks of gestation by emergent cesarean section because of non-reassuring fetal status. Her mother had severe eating disorder and recurrent vomiting since early pregnancy. She was immediately intubated and ventilated because she was extremely pale, hypotonic, and non-reactive. Cerebral magnetic resonance imaging immediately after birth showed intraparenchymal hemorrhage in the left frontal lobe and cerebellum, marked cerebral edema, and cerebellar hypoplasia. Coagulation studies of the infant showed hepaplastin test <5%, prolonged PT and APTT, and a marked elevation of protein induced by vitamin K absence or antagonist-II. This case highlighted a potential risk of intracranial bleeding due to maternal vitamin K deficiency and difficulty in its prediction before delivery. Vitamin K supplementation to high risk mothers might be indispensable for preventing severe fetal vitamin K deficiency. Even when coagulation studies in mothers is normal, it is imperative to provide vitamin K supplementation for total protection.

Dietary reference values for vitamin K

Following a request from the European Commission, the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) derives dietary reference values (DRVs) for vitamin K. In this Opinion, the Panel considers vitamin K to comprise both phylloquinone and menaquinones. The Panel considers that none of the biomarkers of vitamin K intake or status is suitable by itself to derive DRVs for vitamin K. Several health outcomes possibly associated with vitamin K intake were also considered but data could not be used to establish DRVs. The Panel considers that average requirements and population reference intakes for vitamin K cannot be derived for adults, infants and children, and therefore sets adequate intakes (AIs). The Panel considers that available evidence on occurrence, absorption, function and content in the body or organs of menaquinones is insufficient, and, therefore, sets AIs for phylloquinone only. Having assessed additional evidence available since 1993 in particular related to biomarkers, intake data and the factorial approach, which all are associated with considerable uncertainties, the Panel maintains the reference value proposed by the Scientific Committee for Food (SCF) in 1993. An AI of 1 μg phylloquinone/kg body weight per day is set for all age and sex population groups. Considering the respective reference body weights, AIs for phylloquinone are set at 70 μg/day for all adults including pregnant and lactating women, at 10 μg/day for infants aged 7-11 months, and between 12 μg/day for children aged 1-3 years and 65 μg/day for children aged 15-17 years.

[Specificities of neonatal hemostasis and implications in pathologic situations]

The haemostasis of healthy newborn differs from those of normal adult but remains well balanced without bleeding or thrombosis. However, this equilibrium is unstable, and the neonate is exposed to acquired or inherited haemostasis disorders that necessitate to be early diagnosed in order to be appropriately treated. Several studies provided reference ranges for haemostatic components in the foetus, the newborn and throughout childhood. The particularities of neonatal haemostasis are therefore better defined and contribute to further understand the pathophysiology and characteristics of hemorrhagic and thrombotic disorders that occur in newborns. Some examples of the impact of age on haemostasis are: the risk of neonatal alloimmune thrombocytopenia is high in the first newborn of a woman at risk since the involved antigens are fully expressed by foetal platelets; the newborn is at risk for vitamin K deficiency with bleeding due to poor transport of vitamin K across the placenta and low levels of coagulation factors II, VII, IX, X; the diagnosis of some inherited coagulation deficiencies can be difficult in the newborn due to physiologically low levels of coagulation factors; thrombotic events are rare in the healthy neonate, despite physiologically very low levels of several coagulation inhibitors; the pharmacokinetic and effects of antithrombotic agents are influenced by the specificities of haemostasis in neonates. This review will discuss about the foetal development of haemostasis until birth, and some implications regarding the pathophysiology, the diagnosis and the treatment of bleeding disorders in the human neonate.

Vitamin K the basics--what's new?

Relatively little is known about the vitamin K status and requirements in term and preterm infants, though hemorrhagic disease of the newborn infant continues to be a worldwide problem. This brief review of vitamin K metabolism, vitamin K dependent proteins, and the vitamin K cycle covers some new thoughts about the importance of vitamin K to human health including the preterm infant. A review of perinatal vitamin K metabolism concludes that little vitamin K actually crosses the placenta from mother to infant. The neonatal sources of vitamin K are generally limited to the vitamin K prophylaxis given at the time of birth, dietary sources, and questionable amounts from vitamin K present in the intestinal tract synthesized from bacteria. Preterm infants receive large quantities of vitamin K from prophylaxis, TPN solutions, infant formula and breast milk fortifiers. Thus, vitamin serum concentration in preterm infants is up to one hundred times higher than those found in adults and 10-20 times those found in term formula-fed infants. Though no toxicity has been reported, the elevation of epoxide reductase (VKOR) from the vitamin K cycle found in the serum of preterm infants is worthy of additional study. PIVKA-II (abnormal prothrombin) is not a reliable indicator of vitamin K deficiency in preterm or term infants.

The evaluation and management of neonatal coagulation disorders

Neonatal hemostatic abnormalities can present diagnostic and therapeutic challenges to the physician. Developmental deficiencies and/or increases of certain coagulation proteins, coupled with acquired or genetic risk factors, can result in a hemorrhagic or thromboembolic emergency. The timely diagnosis of a congenital hemorrhagic or thrombotic disorder can avoid significant long-term sequelae. However, due to the lack of randomized clinical trials addressing the management of neonatal coagulation disorders, treatment strategies are usually empiric and not evidence-based. In this chapter, we will review the neonatal hemostatic system and will discuss the most common types of hemorrhagic and thrombotic disorders. Congenital and acquired risk factors for hemorrhagic and thromboembolic disorders will be presented, as well as current treatment options. Finally, suggested evaluations for neonates with either hemorrhagic or thromboembolic problems will be reviewed.

[Fat-soluble vitamins in infants]

Vitamins are micronutrients not synthesised by the human body and should be provided by the nutrition. Liposoluble vitamins include vitamins A, E, D and K. Vitamins A and E are two potent antioxidant nutrients and play a significant role in immune function. Vitamin D plays a major role in intestinal calcium absorption and bone mineralization. Vitamin K intervenes in the synthesis of coagulation factors particularly in the prothrombin synthesis. Vitamin metabolism, placental transfer, vitamin status in newborns and infants are reported. Finally requirements of these vitamins are defined.

Development of coagulation regulatory proteins in the fetal and neonatal lamb

To investigate the development of coagulation regulatory proteins-protein C (PC), protein S (PS), and antithrombin (AT)-in relationship to the procoagulant protein factor X (FX), a chronically catheterized fetal ovine model was used. Infusion and sampling catheters were placed into pregnant ewes and their fetuses and maintained from mid-gestation. From a total of 110 fetuses, 17 lambs, and 63 ewes that were studied on one to 15 occasions, 212 fetal, 88 neonatal, and 157 maternal samples were obtained. Liver tissue was obtained from 31 fetuses and 15 ewes. Plasma levels of all proteins studied were higher in the ewe than in the fetus (p < 0.0001). Plasma levels of FX, PC, and PS achieved neonatal levels by mid-gestation with mild but significant decreases during mid- and late gestation. Fetal and early neonatal plasma concentrations of these vitamin K-dependent proteins fit a model with both quadratic (p < 0.01) and linear (p < 0.01) components. The discrepant levels in mRNA relative to plasma concentration were consistent with regulatory control beyond the level of transcription. In contrast, a simple linear increase in plasma protein levels was determined for the vitamin K-independent coagulation regulatory protein, AT (p for quadratic component > 0.05). This study suggests that fetal regulation of coagulation proteins follows characteristic patterns relative to the vitamin K dependence of the protein rather than its role as a procoagulant versus regulatory protein.

Vitamin K status of premature infants: implications for current recommendations

OBJECTIVE

Newborn infants are vitamin K deficient. Vitamin K status in full-term infants after intramuscular vitamin K supplementation at birth has been described. Similar information in growing premature infants has not been reported. The objective of this study was to assess vitamin K status in premature infants by measuring plasma vitamin K and plasma protein-induced in vitamin K absence (PIVKA II) from birth until 40 weeks' postconceptional age.

METHODS

Premature infants (</=36 weeks' gestation) were divided at birth into groups by gestational age (group 1, </=28 weeks; group 2, 29-32 weeks; group 3, 33-36 weeks). Supplemental vitamin K (1 mg intramuscularly) was administered at birth followed by 60 microg/day (weight <1000 g) or 130 microg/day (weight >/=1000 g) via total parenteral nutrition. After hyperalimentation, most received vitamin K-fortified enteral feedings with the remainder receiving unfortified breast milk. Blood was obtained for PIVKA II in cord blood and for PIVKA II and vitamin K at 2 weeks and 6 weeks after birth and at 40 weeks' postconception.

RESULTS

Of the 44 infants enrolled, 10 infants in each gestational age group completed the study. The patient characteristics for groups 1, 2, and 3 were as follows: gestational age, 26.3 +/- 1.7, 30.3 +/- 1.3, and 33.9 +/- 1.1 weeks; birth weight, 876 +/- 176, 1365 +/- 186, and 1906 +/- 163 g; and days of hyperalimentation, 28.9 +/- 16, 16.8 +/- 12, and 4.3 +/- 4 days, respectively. At 2 weeks of age, the vitamin K intake and plasma levels were highest in group 1 versus group 3 (intake: 71.2 +/- 39.6 vs 13.4 +/- 16.3 microg/kg/day; plasma levels: 130.7 +/- 125.6 vs 27.2 +/- 24.4 ng/mL). By 40 weeks' postconception, the vitamin K intake and plasma levels were similar in all 3 groups (group 1, 2, and 3: intake, 11.4 +/- 2.5, 15.4 +/- 6.0, and 10.0 +/- 7.0 microg/kg/day; plasma level, 5.4 +/- 3.8, 5.9 +/- 3.9, and 9.3 +/- 8.5 ng/mL). None of the postnatal plasma samples had any detectable PIVKA II.

CONCLUSIONS

Premature infants at 2 weeks of age have high plasma vitamin K levels compared with those at 40 weeks' postconceptional age secondary to the parenteral administration of large amounts of vitamin K. By 40 weeks' postconception, these values are similar to those in term formula-fed infants. Confirming "adequate vitamin K status," PIVKA II was undetectable by 2 weeks of life in all of the premature infants. With the potential for unforeseen consequences of high vitamin K levels, consideration should be given to reducing the amount of parenteral vitamin K supplementation in the first few weeks of life in premature infants.vitamin K, PIVKA II, premature, total parenteral nutrition, enteral nutrition.

Fat-soluble vitamin supplements for enterally fed preterm infants

Fat-soluble vitamin requirements for the enterally fed premature infant are an important concern, both before and after discharge from the neonatal intensive care unit. Because preterm infants fed unsupplemented human milk receive deficient quantities of these vitamins (A, D, E, and K), supplements are very important for this population. Vitamin intakes with special formulas for low birth weight infants and human milk fortifiers are also reviewed.

Vitamin metabolism and requirements in the micropremie

Vitamin metabolism and requirements are reviewed for the micropremie (1000 Pounds g birthweight), for parenteral and enteral feedings. Recommendations are presented in table format. Human milk fortifiers and special formulas for the preterm infant are reviewed. For parenteral nutrition, only MVI Pediatric is currently available in the United States. Two millimeters per kilogram is recommended for the micropremie as the most satisfactory method of providing supplemental vitamins in total parenteral nutrition solutions.

Developmental changes of vitamin K epoxidase and reductase activities involved in the vitamin K cycle in human liver

We examined the developmental changes in activities of vitamin K epoxidase, and vitamin K-2,3-epoxide reductase and vitamin K reductase in the human autopsied liver. The activity of epoxidase, which converts vitamin K hydroquinone to its epoxide, showed a high value in the early prenatal period of 10-30 gestational weeks but decreased rather rapidly in contrast with the reductase activities. After birth, a significant decrease of the epoxidase activity was observed but no such change was seen during the postnatal period. On the other hand, the activities of vitamin K-2,3-epoxide reductase and vitamin K reductase, which convert vitamin K-2,3-epoxide to its hydroquinone, showed a significantly low value in the early prenatal period. The highest activity of vitamin K epoxidase in the early prenatal period may be essential to the production of vitamin K dependent ligands for growth factors expressed in the embryo.

Interdependence of serum concentrations of vitamin K1, vitamin E, lipids, apolipoprotein A1, and apolipoprotein B: importance in assessing vitamin status

Vitamin E (alpha-tocopherol) and vitamin K1 (phylloquinone) are fat-soluble vitamins and are important nutrients in health and disease. In this study serum concentrations of vitamin E and vitamin K1, lipids and apolipoproteins A1 and B were measured in neonates, normal and hyperlipidaemic individuals in an attempt to establish their interrelationships. A high degree of correlation was observed between the concentrations of the vitamins and those of lipids and apolipoproteins (r ranged from 0.42 to 0.92; p<0.001). Stepwise linear regression methods determined that serum concentrations of both vitamin E and vitamin K1 could best be predicted by using equations excluding lipids but containing only apolipoprotein A1 and B concentrations. Correlation coefficients between predicted and measured values were 0.89 for serum vitamin E, and 0.83 for serum vitamin K1 concentrations. To test the validity of the derived formulae, measured and estimated vitamin K1 and vitamin E concentrations in serum were determined in another group of neonates, normal adults and hypercholesterolemic adults and the comparisons were shown to be very good. These results indicate that the serum levels of both vitamins depend critically on the concentration of the lipoprotein carriers, apolipoproteins A1 and B. Hence, in order to identify variations in serum vitamin K1 and vitamin E concentrations, which are independent of variations in carrier concentration, it will be necessary to express these serum vitamins as ratios of vitamins to apolipoprotein A1 and B carriers.

Vitamin K status of lactating mothers and their infants

Vitamin K deficiency remains a world-wide problem in the newborn. Vitamin K traverses the placenta from mother to infant very poorly and is present only in very low concentrations in human milk. Thus, it is not surprising that the newborn infant has undetectable vitamin K serum levels with abnormal amounts of the coagulation proteins and undercarboxylated prothrombin. Hemorrhagic disease of the newborn, secondary to vitamin K deficiency, remains largely a disease of breastfed infants. Lactating mothers easily achieve the recommended dietary allowance for vitamin K (1 microg kg(-1) d(-1)) and the breast milk concentration is readily increased by increasing maternal vitamin K intake. Breastfed infants do not receive the recommended vitamin K intake via human milk. To prevent vitamin K deficiency in the newborn, intramuscular or oral vitamin K prophylaxis is necessary.

Prothrombin and PIVKA-II levels in cord blood from newborn exposed to anticonvulsants during pregnancy

PURPOSE

To determine whether anticonvulsant exposure during human pregnancy caused an increase of the abnormal form of prothrombin, known as PIVKA-II (prothrombin induced by vitamin K absence for factor II), and a decrease in total prothrombin, in the blood of the newborn.

METHODS

Cord blood was collected from the placenta at the time of parturition from 12 women who had received anticonvulsant therapy during pregnancy and from 11 control women.

RESULTS

PIVKA-II was present in cord blood from control mothers at low or nondetectable levels. In the same samples, total prothrombin concentrations were approximately 50% of adult levels, but there was wide variation between individuals. Exposure to carbamazepine (CBZ) alone during pregnancy was associated with markedly increased PIVKA-II levels in four of six samples and decreased total prothrombin levels for the whole group. High PIVKA-II levels also were recorded in one cord blood sample from a mother who received phenytoin (PHT) and vigabatrin (VGB). Two cases of PHT alone and one of valproic acid (VPA) alone were not associated with increased PIVKA-II levels.

CONCLUSIONS

These results are consistent with the hypothesis that some anticonvulsants (particularly CBZ) interfere with vitamin K metabolism during pregnancy and may result in hematologic signs of vitamin K deficiency in the newborn.

The relevance of developmental hemostasis to hemorrhagic disorders of newborns

The hemostatic system is a dynamic evolving process that is age-dependent. Components of the hemostatic system are synthesized in early fetal life and do not cross the placenta from mother to fetus. However, plasma concentrations of proteins involved in hemostasis significantly differ from adults. Physiological reference ranges are available for premature infants, full-term infants and children from ages 1 to 16 years. In the coagulation system, plasma concentrations of the vitamin K-dependent and contact factors are decreased at birth, whereas other factors such as fibrinogen, FV, FVIII, and FXIII are similar or increased compared with adults at birth. In the fibrinolytic system, plasma concentrations of plasminogen are decreased at birth, whereas tissue plasminogen activator and plasminogen activator inhibitor are increased. Clinically, the hemostatic system of the young is effective and healthy infants do not suffer from spontaneous hemorrhagic complications. However, infants are more vulnerable, compared with older patients, for bleeding in the presence of either congenital or acquired haemostatic defects. Severe congenital bleeding disorders, although rare, frequently present in the newborn period. The most common acquired causes of bleeding newborns include disseminated intravascular coagulation, vitamin K deficiency, and liver disease. A description of these disorders and treatment guidelines are provided.

Prenatal exposure to phenytoin, facial development, and a possible role for vitamin K

Ten patients with maxillonasal hypoplasia (Binder "syndrome"), who were prenatally exposed to phenytoin (usually in combination with other anticonvulsants), were identified retrospectively. In addition to their facial anomalies, 6 of the patients were radiographed neonatally and showed punctate calcification, characteristic of chondrodysplasia punctata. Evidence is presented that the facial abnormalities seen in these children are due to anticonvulsant-induced vitamin K deficiency, causing abnormal development of the cartilaginous nasal septum. We propose that early vitamin K supplementation of at-risk pregnancies may prevent the development of maxillonasal hypoplasia, which in some patients is severely disfiguring and causes great emotional distress. Correction of this facial defect requires surgical and dental treatment over a long period of time.

Vitamin K--its essential role in craniofacial development. A review of the literature regarding vitamin K and craniofacial development

The normal vitamin K status of the human embryo appears to be close to deficiency. Maternal dietary deficiency or use of a number of therapeutic drugs during pregnancy, may result in frank vitamin K deficiency in the embryo. First trimester deficiency results in maxillonasal hypoplasia in the neonate with subsequent facial and orthodontic implications. A rat model of the vitamin K deficiency embryopathy shows that the facial dysmorphology is preceded by uncontrolled calcification in the normally uncalcified nasal septal cartilage, and decreased longitudinal growth of the cartilage, resulting in maxillonasal hypoplasia. The developing septal cartilage is normally rich in the vitamin K-dependent protein matrix gla protein (MGP). It is proposed that functional MGP is necessary to maintain growing cartilage in a non-calcified state. Developing teeth contain both MGP and a second vitamin K-dependent protein, bone gla protein (BGP). It has been postulated that these proteins have a functional role in tooth mineralization. As yet this function has not been established and abnormalities in tooth formation have not been observed under conditions where BGP and MGP should be formed in a non-functional form.

Antenatal vitamin K therapy of the low-birth-weight infant

OBJECTIVE

The purpose of our study was to determine whether maternal vitamin K1 administered antenatally improved global coagulation parameters and the levels of specific vitamin K-dependent proteins in low-birth-weight infants.

STUDY DESIGN

Thirty-three preterm mothers admitted in labor were assigned in a prospective, blinded fashion to receive either intramuscular vitamin K1 (17) or placebo (16). At delivery cord blood samples were tested for prothrombin time, activated partial thromboplastin time, factor II and protein C activity, and antigen levels. Statistical analysis was by Student t test.

RESULTS

No statistically significant differences could be demonstrated with regard to group mean values for global tests (prothrombin time, activated partial thromboplastin time) or specific vitamin K-dependent protein levels (factor II, protein C) in newborns whose mothers received antenatal vitamin K compared with those who did not.

CONCLUSION

These results would suggest that antenatal vitamin K1 therapy to mothers < 32 weeks' gestation has no significant effect on the level of vitamin K-dependent factors in the fetus.

Epilepsy and pregnancy

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Supplementation of vitamin K in pregnant women receiving anticonvulsant therapy prevents neonatal vitamin K deficiency

OBJECTIVE

The null hypothesis of this study is that extra vitamin K administered to pregnant women on a regimen of enzyme-inducing anticonvulsant therapy will not decrease the frequency of symptoms of vitamin K deficiency in their neonates.

STUDY DESIGN

A multicenter case-control study was performed on 16 pregnant women on anticonvulsant therapy who received 10 mg of vitamin K1 daily from 36 weeks of pregnancy onward. Concentrations of PIVKA-II (protein induced by vitamin K absence for factor II) and of vitamin K1 were determined in cord blood and compared with those in 20 controls.

RESULTS

In none of 17 cord samples was PIVKA-II detectable, compared with 13 of 20 in controls (chi 2, p < 0.001). Median cord vitamin K1 level was 530 pg/ml compared with below detection limit in most controls.

CONCLUSIONS

Antenatal vitamin K1 treatment decreases the frequency of vitamin K deficiency in neonates of mothers on anticonvulsant therapy.

Vitamin K coagulation status in surgical newborns and the risk of bleeding

The vitamin K coagulation status in surgical newborns, who may be at increased risk of developing hypocoagulability and hemorrhage, has not previously been studied. Therefore, we measured the combined activity of the plasma vitamin K-dependent coagulation factors (Thrombotest), total prothrombin, PIVKA II, plasma vitamin K1, fibrinogen, D-Dimer, and platelets in 49 newborns admitted to a neonatal surgical intensive care unit. All infants had significant pathology, and treatment involved surgery in all but two. Twenty-three infants (47%) underwent surgery on two or more occasions. Intravenous or oral antibiotics were used in all patients and many received more than one course. All infants had vitamin K1 prophylaxis at birth. At day 0 (date of birth), the mean Thrombotest and total prothrombin levels were 51% (range, 20% to 100%) and 40% (range, 24% to 59%), respectively. Coagulation activity decreased on day 1 (P > .1) and was followed by a graduate increase in clotting activity, reaching normal adult levels (> 60%) at day 5 for Thrombotest and day 24 for total prothrombin. Only three infants had a Thrombotest less than 20%. PIVKA II was detected in 20 cases (41%). However, levels were within normal limits (< 0.9%) in 17 of these, and between 1.0 and 4.8% in the remaining three infants. There was no relationship between elevated PIVKA levels and coagulation activity in these patients. Plasma vitamin K1 was very high, particularly in the first days of life.(ABSTRACT TRUNCATED AT 250 WORDS)

Binder's syndrome due to prenatal vitamin K deficiency: a theory of pathogenesis

There is evidence that vitamin K-deficiency during human pregnancy can be caused by the therapeutic use of warfarin or phenytoin. The pregnancy histories of three cases of Binder's syndrome are reported. One was associated with warfarin exposure, one with phenytoin exposure and one with alcohol abuse. It is proposed that Binder's syndrome can be caused by prenatal exposure to agents that cause vitamin K-deficiency. Sprague-Dawley rats were treated from postnatal day 1 to 12 weeks with daily doses of warfarin (100 mg/kg) and concurrent vitamin K1 (10 mg/kg). This regimen creates a net extra-hepatic vitamin K-deficiency. The treated rats developed with a distinct facial appearance characterized by a markedly reduced snout. Histological examination showed that the normally non-calcified septal cartilage was extensively calcified. It is proposed that normal growth of the septal cartilage is necessary for the development of the profile of the nose and midface and that normal growth will only take place while the septal cartilage is uncalcified.

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.

Exposure of the pregnant rat to warfarin and vitamin K1: an animal model of intraventricular hemorrhage in the fetus

Pregnant Sprague-Dawley rats were given daily oral doses of sodium warfarin (100 mg/kg) and concurrent intramuscular injections of vitamin K1 (10 mg/kg). This dosing regimen did not have any apparent deleterious effect on the dams and did not affect the fetuses when administered from day 1 to day 12 of pregnancy. However, similar treatment from day 9 to 20 caused hemorrhage in the fetuses examined on day 21 of gestation. There were no hemorrhages in the control fetuses from dams receiving vitamin K1 only. The lowest effective dose of warfarin, in conjunction with daily doses of vitamin K1, was 3 mg/kg. This dose caused hemorrhage in 28% of fetuses; the incidence of affected fetuses was not further increased by doses of warfarin up to 100 mg/kg. Hemorrhages affected the fetal brain, face, eyes, and ear and occasionally the limbs. Brain hemorrhages were frequently intraventricular and caused various degrees of hydrocephaly. Bony defects were not a feature of prenatal exposure to warfarin. These results show that prenatal exposure of the rat to warfarin and vitamin K duplicates the hemorrhagic abnormalities and pathology associated with prenatal exposure to warfarin in the human. It did not induce bony or facial defects probably because the vitamin K-dependent components of bone development occur postnatally in the rat. This model should allow detailed determination of the role of vitamin K-dependent proteins in development.