Venous thromboembolism, comprised of deep vein thrombosis and pulmonary embolism, is commonly found during or shortly after hospital stays. To prevent such events, processes of thromboprophylaxis have emerged for all types of inpatients through the use of low-dose anticoagulants (heparins or low-molecular-weight heparins). In this thesis, the evidence behind thromboprophylaxis in medical and obstetrical inpatients is reviewed, including my own research in these fields. While there are many differences between these populations, our approach remains very simplistic, with one similar treatment for all high-risk patients and no treatment for low-risk patients. Reflections on how to bring more granularity to medical thromboprophylaxis and stronger evidence to obstetrical thromboprophylaxis are discussed.