The platelet hyporeactivity of extremely low birth weight neonates is age-dependent

Thromb Res. 2009 May;124(1):42-5. doi: 10.1016/j.thromres.2008.10.004. Epub 2008 Nov 20.


Introduction: We have previously demonstrated that, as compared to adults, the platelets of extremely low birth weight (ELBW) neonates are markedly hyporeactive on day 0-1 of life. The purpose of this study was to examine the age dependency of this hyporeactivity.

Materials and methods: On days 0-1, 3-4, and 10-14, peripheral blood was collected from 14 stable ELBW neonates and compared to peripheral blood from normal adults run in parallel. Whole blood flow cytometry was used to examine the activation-dependent increase in platelet surface P-selectin (reflecting degranulation) and platelet surface binding of factor V/Va (reflecting platelet surface procoagulant activity) and decrease in platelet surface glycoprotein (GP) Ib (the von Willebrand factor receptor).

Results: In the physiologic milieu of whole blood, ELBW neonatal platelets on days 0-1 and 3-4 were markedly less reactive than adult platelets. However, by day 10-14, the platelet function of ELBW neonates improved significantly, although not completely to adult levels.

Conclusions: The age-dependent platelet hyporeactivity of ELBW neonates demonstrated in this study may be a contributing factor to the similar age-dependent propensity of ELBW neonates to intraventricular hemorrhage.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Age Factors
  • Blood Platelets / metabolism*
  • Factor V / metabolism*
  • Factor Va / metabolism*
  • Humans
  • Infant, Extremely Low Birth Weight
  • Infant, Newborn
  • P-Selectin / metabolism*
  • Platelet Glycoprotein GPIb-IX Complex / metabolism*


  • P-Selectin
  • Platelet Glycoprotein GPIb-IX Complex
  • Factor Va
  • Factor V