Platelet count and function in umbilical cord blood versus peripheral blood in term neonates.

Platelet function in neonates is sparsely investigated. The majority of previous studies investigated platelets in umbilical cord (UC) blood rather than in peripheral blood.We included 20 term neonates and sampled UC blood and peripheral blood within 20 min and 24 h after birth. Platelet count and mean platelet volume (MPV) were measured. Platelet surface glycoproteins (GP) and platelet activation (bound fibrinogen, CD63 and p-selectin) after agonist stimulation were examined by flow cytometry. Platelet aggregation was evaluated by impedance aggregometry. The significance level was set after Bonferroni correction.Platelet count and MPV did not differ between UC and peripheral blood (p-values >0.08). Expression of platelet surface GP was similar in UC and peripheral blood (all p-values >0.02). Platelet activation was lower in UC blood than in peripheral blood for bound fibrinogen (four out of eight p-values <0.001) but did not differ for CD63 (all p-values >0.01) or P-selectin (all p-values >0.01). Platelet aggregation was significantly higher in UC than in peripheral blood (p-values <0.001).In conclusion, platelet count, MPV and expression of platelet surface GP measured in term neonatal UC blood represented that of peripheral blood. Platelet activation and aggregation in UC blood did not reflect that of peripheral blood.