title: Vitamin K deficiency in the newborn infant: prevalence and perinatal risk factors.
abstract: The prevalence of vitamin K deficiency in newborn infants and the influence of perinatal risk factors were studied prospectively in 934 infants. A noncarboxylated prothrombin assay to detect proteins induced in vitamin K absence (PIVKA-II) was used to determine the presence of vitamin K deficiency; of 934 cord blood samples assayed, 2.9% were positive for PIVKA-II (0.015 to 0.15 U/ml). All infants found to have detectable PIVKA-II were born at term. The number of infants positive for PIVKA-II was greater in the group small for gestational age (7.4%) than in those appropriate (2.7%) or large (3.1%) for gestational age. Nine categories of perinatal risk groups were defined: however, the majority of infants who were PIVKA-II positive (63%) were normal. All infants received prophylactic vitamin K, and no infant with PIVKA-II in the cord sample subsequently had clinical bleeding. In two patients the rate of 50% disappearance of PIVKA-II after vitamin K administration approximated 70 hours. Two PIVKA-II positive patients with active bleeding or disseminated intravascular coagulation had an accelerated disappearance of 20 to 40 hours. The long disappearance time of PIVKA-II in a steady state may allow detection of vitamin K deficiency despite administration of vitamin K. The majority of cases of neonatal vitamin K deficiency occurred in normal newborn infants. Therefore, all infants should receive prophylactic vitamin K at birth.
mesh_terms: D015415:Biomarkers; D005312:Fetal Blood / Q000032:analysis; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age / Q000097:blood; D011446:Prospective Studies; D011498:Protein Precursors / Q000032:analysis*; D011516:Prothrombin / Q000032:analysis*; D012306:Risk; D014812:Vitamin K / Q000627:therapeutic use; D014813:Vitamin K Deficiency / Q000097:blood* / Q000517:prevention & control
chemical_list: D015415:Biomarkers; D011498:Protein Precursors; D014812:Vitamin K; C008208:acarboxyprothrombin; D011516:Prothrombin