Soon after the introduction of hormonal oral contraceptive agents reports of thrombotic complications appeared. In the past several decades, large epidemiological studies helped defined these risks for both arterial and venous complications. Clinicians can assess a patient's risk of thrombosis by both composition of the agent and patients' personal risk factors. For women with bleeding disorders these prothrombotic changes can help decrease bleeding complications. There is now also abundant data on future management of patients with estrogen related thrombosis.