Venous thromboembolic VTE complications are leading causes of maternal mortality in the developed world. Over the past 20 years, there has been an increase in the incidence of deep venous thrombosis DVT in pregnant women, and this increase may be explained by the risk factors including older age, cesarean section, history of VTE, and presence of thrombophilia. To reduce the incidence of VTE in pregnancy and improve the outcomes, a wider understanding of the risk factors, and a better identification of women at risk of the thrombosis, with objective diagnosis and provide the optimal effective and safe treatment. Deep venous thrombosis and pulmonary embolism, considered manifestations of the same disease, are often preventable and usually treatable. Nevertheless, VTE remains a substantial problem despite the dramatic decline in pregnancy-related mortality in industrialized countries over the past century. While diagnosis and management of VTE in pregnancy are challenging, and many diagnostic tests are less accurate in pregnant than non-pregnant patients, and the available options are suboptimal. This is a review in 2 parts, in part I, we address the following questions: In pregnant women, who developed DVT; how to diagnose, and the treatment once the diagnosis is confirmed. For each of these problems, the relevant background is briefly summarized, approaches recommended, and the suggested practical and relatively safe diagnostic management approaches. Part II, we address pregnant women with pulmonary embolism, how to diagnose and treat.