Purpose of review: Hormone therapy increases the risk of venous thromboembolism (VTE). To reduce this risk, changes in dosage, composition and route of administration have been made over the years. This review provides a summary of the available evidence and an update on the most recent findings on the issue.
Recent findings: Contraceptives containing third-generation progestagens confer a higher risk of VTE than second-generation compounds. Little data are available on preparations containing less than 30 μg of estrogen, new progestagens or levonorgestrel-releasing intrauterine devices. Hormone replacement therapy increases the risk of VTE by 2 to 3-fold. Transdermal administration may be less thrombogenic than oral administration, while different estrogens and progestagens may carry a different risk. VTE risk is further increased in carriers of inherited thrombophilia. Despite a similar increase in relative risk of thrombosis associated with hormone therapy, absolute risk is lower in fertile women and higher in postmenopausal ones. Universal screening for thrombophilia before prescribing hormone replacement therapy might be cost-effective.
Summary: Careful evaluation of individual risk factor is warranted before prescribing hormone therapy. Further investigations are needed to establish whether or not newer compounds are safer than older ones with respect to the risk of thrombosis.