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, gammacarboxy 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, 220% 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 gammacarboxy 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 corcorrelated with the PIVKA-II concentrations. These findings suggest that simultaneous gammacarboxylation 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. Therefore, mothers should be advised to try to increase the breast milk secretion, for example, by providing frequent sucklings to infants in the first days of life. (Arch Dis Child 1993;68:297-302) Vitamin K is required for the post-translational gammacarboxylation of glutamic acid residues in the vitamin K dependent proteins,' including not only coagulation factors II, VII, IX, and X but also protein C2 and protein S,3 which are the important inhibitors of coagulation.4-7 Vitamin K deficiency results in the biosynthesis of abnormal non-gammacarboxy forms of these proteins which are functionally defective. Dysfunction of these coagulation factors and inhibitors are clinically well known and seen in such diseases as haemorrhagic disease of the newborn8-10 and thromboembolic disorders including neonatal purpura fulminans.1 1-5 As vitamin K deficiency in the early neonatal period causes haemorrhagic diseases rather than thromboembolic disorders, vitamin K deficiency has been viewed exclusively from its relevance to coagulation factors.We report our study of the changes of protein C and protein S as well as of coagulation factors from the occurrence of vitamin K deficiency to its correction with vitamin K administration. Furthermore, the relationship between the breast milk intake and vitamin K deficiency in neonates was also investigated.
Subjects and methods
SUBJECTSSixty six healthy, full term (range 38-41 weeks) neonates with a normal birth weight (range 2755-3970 g) aged 0 to 6 days were studied. There was no history of mater...