title: Vitamin K1 levels and K1-dependent coagulation factors II and X in preterm and small-for-date neonates.
abstract: In 17 preterm neonates and 7 small-for-date neonates, all formula-fed, vitamin K-dependent coagulation factors II and X remained near 45% of adult values from the moment of birth until 28 days postnatally. Vitamin K1 levels, however, showed a remarkable rise from below the detection limit of 0.022 ng/ml in umbilical cord blood, to serum levels with a range of 0.99-7.29 ng/ml vitamin K1 on day 3, with a further rise on days 7 and 28 postnatally. Vitamin K1 (Konakion) parenterally given to a third group of four preterm neonates as a 1 mg dose resulted in very high serum levels of vitamin K1 (64.08-157.10 ng/ml), but without any significant increase in plasma levels of vitamin K-dependent coagulation factors II and X, compared to the group without any extra vitamin K1. It is concluded that in healthy preterm and small-for-date neonates no correlation is seen between serum levels of vitamin K1 and plasma levels of coagulation factors II and X. After administration of 1 mg Konakion no accelerated increase is seen in coagulation factor activities.
authors.affiliation: Department of Obstetrics and Gynaecology, Reinier de Graaf Hospital, Delft, The Netherlands.
authors.forename: A L
authors.initials: AL
authors.lastname: Pietersma-de Bruyn
authors.forename: P J
authors.initials: PJ
authors.lastname: van der Straaten
authors.forename: P M
authors.initials: PM
authors.lastname: van Haard
authors.forename: J C
authors.initials: JC
authors.lastname: Kuijpers
authors.forename: K
authors.initials: K
authors.lastname: Hamulyák
authors.forename: J H
authors.initials: JH
authors.lastname: Ruys
mesh_terms: D005170:Factor X / Q000032:analysis*; D005312:Fetal Blood / Q000032:analysis; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000097:blood*; D007236:Infant, Small for Gestational Age / Q000097:blood*; D011516:Prothrombin / Q000032:analysis*; D010837:Vitamin K 1 / Q000097:blood*; D006475:Vitamin K Deficiency Bleeding / Q000209:etiology
chemical_list: D010837:Vitamin K 1; D011516:Prothrombin; D005170:Factor X