Summary
The aggregation of platelets collected from maternal/neonatal pairs (n = 240) at the
time of childbirth, was studied in response to multiple doses of ADP, collagen, arachidonic
acid and ristocetin. Similar responses were obtained from healthy nonpregnant adult
controls for comparison. The lag phase, slope of the aggregation curves as well as
maximum aggregation (MA%) were recorded and analysed. Neonatal and adult platelets
exhibited more enhanced responses to decreasing doses of ADP, arachidonic acid and
ristocetin, than maternal platelets. These enhanced responses were exhibited more
consistantly in the slopes of the aggregation curves than in MA%. Although neonatal
platelets have shown longer lag phase in their responses to collagen, the rate of
the aggregation reaction was significantly faster than maternal platelets, with no
differences in MA%. These results contradict many previous reports suggesting impaired
aggregation responses of neonatal platelets to these agonist. The possible reasons
for these contradictions were discussed.
Keywords
Blood platelets - Aggregation - Dose response - Neonates
