[Preeclampsia not (yet) predictable from the blood platelet count]

Platelet activation plays an important role in the pathogenesis of pre-eclampsia as demonstrated by reduced platelet count, increased mean platelet volume and elevated plasma concentrations of beta-thromboglobulin and platelet factor 4 in pre-eclamptic patients. Thrombocytopenia precedes the onset of clinical symptoms of pre-eclampsia. Possibly an enhanced activation state of the platelets in the circulation is present some time before the onset of pre-eclampsia: platelet activation might then be used to predict pre-eclampsia. Flow cytometry is considered the most sensitive technique at this moment to measure the activation of platelets. Fluorescent-labelled antibodies are used to detect antigens that appear on the platelet surface or change their conformation upon activation. During the first and second trimester of pregnancy pre-eclamptic patients have an increased expression of some antigens on the surface of their platelets, such as CD63. There is no reliable platelet test yet to predict the onset of pre-eclampsia.