Sex hormones and thrombosis.

There is compelling evidence that use of oral formulations of female hormone replacement and of the combined oral contraceptive induces a prothrombotic state. This translates to an increased thrombotic risk. Within the individual, the absolute risk is determined by the interaction between that induced by hormone use and heritable and acquired risk factors for thrombosis. Knowledge of the accumulating epidemiologic and clinical trial-derived data on this topic is essential for the delivery of evidence-based counseling in the clinical environment and is the subject of this review.