Coagulation indices in very preterm infants from cord blood and postnatal samples

Abstract

Summary. Background: Very premature infants are at high risk of bleeding complications; however, few data exist on ranges for standard coagulation tests. Objectives: The primary objective of this study was to measure standard plasma coagulation tests and thrombin generation in very premature infants compared with term infants. The secondary objective was to evaluate whether an association existed between coagulation indices and intraventricular hemorrhage (IVH). Patients/Methods: Cord and peripheral blood of neonates < 30 weeks gestational age (GA) was drawn at birth, on days 1 and 3 and fortnightly until 30 weeks corrected gestational age. Prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen and coagulation factor levels were measured and tissue factor-stimulated thrombin generation was characterized. Control plasma was obtained from cord blood of term neonates. Results: One hundred and sixteen infants were recruited. Median (range) GA was 27.7 (23.7-29.9) weeks and mean (SD) birth weight was 1020 (255) g. Median (5th-95th percentile) day 1 PT, APTT and fibrinogen were 17.5 (12.7-26.6) s, 78.7 (48.7-134.3) s and 1.4 (0.72-3.8) g L À1, respectively. No difference in endogenous thrombin potential between preterm and term plasma was observed, where samples were available. Levels of coagulation factors II, VII, IX and X, protein C, protein S and antithrombin were reduced in preterm compared with term plasma. Day 1 APTT and PT were not associated with IVH. Conclusion: In the largest cross-sectional study to date of very preterm infants, typical ranges for standard coagulation tests were determined. Despite long clotting times, thrombin generation was observed to be similar in very preterm and term infants.

Perinatal Factors Affecting Coagulation Parameters at Birth in Preterm and Term Neonates: A Retrospective Cohort Study

“…Another study suggested that median aPTT and FBG of cord blood in premature infants were 78.7 seconds and 114 mg/dL, respectively. 10 The median aPTT and FBG in preterm infants were 69.8 seconds and 118 mg/dL, respec-tively, in this study. In our study, we collected the sample after vitamin K2 administration.…”

“…Other studies of small sample size have reported values of coagulation factors in preterm neonates. 6,10,13 This study demonstrated that various prenatal factors affected coagulation factors. PT-INR was associated with IVH, PA, and Apgar score at 5 minutes, whereas aPTT was associated with BW, GA, and PA.…”

The Role of Platelets in Premature Neonates with Intraventricular Hemorrhage: A Systematic Review and Meta-Analysis

“…7 Premature neonatal hemostasis is generally characterized by reduced amounts of vitamin K dependent coagulation factors as well as natural anticoagulants, and secondary hemostasis is therefore considered balanced. 8,9 However, derangements in activated partial thromboplastin time (APTT), international normalized ratio (INR), and prothrombin time (PT) have been associated with IVH in premature neonates. 10,11 While thrombocytopenia is common in premature neonates, 12 controversies exist on the role of platelet counts in IVH among the premature neonates.…”

Cardiovascular Alterations and Multiorgan Dysfunction After Birth Asphyxia

“…Plasma levels of thrombin-antithrombin complexes, D-dimer, fibrinogen, and fibrin degradation products are higher in infants with birth asphyxia [69]. It should be noted that levels of coagulation factors II, VII, IX, and X, protein C, protein S and antithrombin are also reduced in preterm compared with term plasma [70]. Prothrombin time (PT) and activated partial thromboplastin time (aPTT) are higher in preterm infants, but there is no correlation with increased risk of intraventricular hemorrhage (IVH) with higher coagulation times [70].…”