Suspected or confirmed venous thromboembolism (VTE) (deep-vein thrombosis and pulmonary embolism) in non-pregnant patients are common clinical problems with ample clinical research upon which diagnostic and treatment recommendations are based. Unfortunately, the level of complexity is increased in the diagnostic and therapeutic management of pregnancy-associated VTE by evolving physiological changes in expectant mothers, the effects of diagnostic and therapeutic management on the unborn child and the lack of validation of these management strategies in pregnancy. This chapter considers the epidemiology, pathogenesis, diagnosis and treatment of pregnancy-associated VTE. It highlights the poverty of research upon which to base clinical recommendations for this common problem yet offers practical but conservative approaches to patients with suspected and confirmed pregnancy-associated VTE.