Summary
The aggregation of platelets from women with pregnancy-induced hypertension (P.I.H.),
or with normal pregnancies, in response to arachidonic acid, ADP, collagen or platelet
activating factor (PAF) was examined. No differences in platelet aggregation between
the normotensive and hypertensive women were detected when arachidonic acid or collagen
were used to stimulate in vitro platelet aggregation. Higher concentrations of ADP
and PAF were required to aggregate platelets from women with P.I.H. compared with
platelets from normotensive controls. Platelets from women with normotensive pregnancies
(n = 80) aggregated maximally in response to 20 nM PAF without exception. Reversible
aggregation by platelets from women with P.I.H. (n = 25) was observed at the same
concentration of PAF; again, this was found in all subjects tested. These results
indicate that PAF at a concentration of 20 nM can clearly demonstrate differences
in aggregation of platelets from women with normotensive pregnancy and women with
P.I.H.
