Summary
The effects of medroxyprogesterone acetate on blood coagulation and platelet collagen
aggregation were studied in nineteen women. After parenteral administration of the
compound for 4 and 7 months, the activated partial thromboplastin time showed a significant
decrease. The percentage of the prothrombin time test rose after 4 months, but not
significantly after 7 months ; factor II decreased after 7 months of treatment. The
reaction time during which no aggregation occurred after addition of a collagen suspension
to a stirred platelet-rich plasma, was shorter after both 4 and 7 months of treatment.
Other coagulation and platelet-function parameters were not altered. Although a trend
toward hypercoagulability was detected, the changes were not the same as those reported
for combined oral contraceptives.
