Neonatal and maternal platelets: activation at time of birth.

Determination of the plasma concentrations of beta-thromboglobulin (BTG), thromboxane B2 (TxB2) and platelet factor 4 (PF4) were made at the time of birth in 18 newborns and their respective mothers. Both groups show significant elevation of all these molecular markers, suggesting marked platelet activation. The elevated TxB2 levels in the newborn group, 25 +/- 8 pg/ml, are compatible with a normally functioning and activated platelet prostaglandin pathway. Mode of delivery, vaginal or caesarean section, does not significantly influence the degree of activation in either group. Ultrastructural platelet examination did not reveal any morphologic differences between maternal and newborn platelets. There appears to be marked activation of the newborn and maternal platelet systems at the time of birth, and we postulate that this may explain in part the transient platelet dysfunction observed in newborns.