Platelet Reactivity and Sex Differences: Clinical Implications for Women

Platelets are central to hemostasis and thrombosis. Excessive platelet activation contributes to arterial thrombotic events, including myocardial infarction, ischemic stroke, and complications of peripheral artery disease, whereas excessive platelet inhibition increases bleeding risk. Antiplatelet therapy remains a cornerstone of secondary prevention in atherosclerotic and thrombotic cardiovascular diseases, yet current treatment paradigms do not fully account for biological heterogeneity in platelet function, including differences related to sex, age, hormonal status, and disease context. This state-of-the-art review examines current antiplatelet strategies, fundamental mechanisms of signal transduction, clinical indications, and limitations of preclinical and clinical studies, with a focus on sex-specific considerations and opportunities for personalized antiplatelet therapy. Aspirin and P2Y₁₂ receptor antagonists are widely used for secondary prevention. However, women have been underrepresented in many pivotal clinical trials, limiting the precision of sex-specific estimates of efficacy and bleeding risk. In parallel, commonly used preclinical models often fail to recapitulate the physiological conditions in which platelets interact with the vasculature, leukocytes, and soluble factors. Emerging therapeutic approaches seek to refine platelet inhibition by targeting pathways that reduce thrombotic risk while preserving hemostasis. Advancing antiplatelet therapy will require integration of mechanistic platelet biology with diverse clinical trial populations, standardized platelet phenotyping, and disease-specific approaches that account for how platelet function is altered across health and vascular disease.