The effect of estrogen replacement therapy on platelet aggregation and adenosine triphosphate release in postmenopausal women

Objective: To evaluate the effect of hormone replacement therapy on platelet function in postmenopausal women. Methods: In 51 postmenopausal women, platelet aggregation and adenosine triphosphate (ATP) release were studied before and after estrogen and progestogen treatment and compared with that in untreated patients. An incubation study evaluated platelet function after incubation with estrogen and progestogen. Results: Significant decreases in adrenaline-induced platelet aggregation (P<.01) and ATP release (P<.02) were observed 3 months after initiation of estrogen replacement