neonatal platelet activation in preeclampsia preeclampsia is associated with an increased platelet activation however there are few studies concerning platelet activation of the newborn the aim of our study was to compare platelet activation in newborns of preeclamptic mothers to newborns of healthy mothers by using whole blood flow cytometry blood samples were obtained from 20 newborns 10 healthy controls 10 cases of preeclampsiahellp hemolysis elevated liver enzymes and low platelet count syndrome during cesarean section antibodies against the following antigens were used as markers for platelet activation cd 41 cd62p cd 63 and plateletbound fibrinogen in addition to the basal platelet activation the ability of platelets to undergo activation as a result of in vitro incubation with a weak agonist adenosine diphosphate was evaluated a significant difference between the groups concerning basal platelet activation could only be seen for plateletbound fibrinogen the control group showed a higher extent of platelet activation 166 113 vs 61 49 p 003 incubation with adenosine diphosphate in the control group resulted in minor increases of platelet activation which was significant only for plateletbound fibrinogen 166 113 vs 425 221 p 002 however the preeclamptic group showed significantly increased levels of platelet activation for all used markers after in vitro activation cd 41 1156 182 vs 1632 296 p 0002 cd62p 24 04 vs 39 03 p 0001 cd 63 27 05 vs 37 06 p 0002 plateletbound fibrinogen 61 49 vs 551 91 p 0001 preeclampsia or hellp syndrome is therefore associated with an increased susceptibility to neonatal platelets even against weak activators such as adenosine diphosphate whether this results from peculiarities in the fetal vascular environment or maternal influences is yet uncertain