The diagnosis of suspected venous thromboembolic disease during pregnancy is problematic because of the fear of fetal irradiation with routine diagnostic procedures. In order to develop rational guidelines, we have calculated levels of radiation exposure to the fetus for the common diagnostic procedures and conducted a literature review to examine the fetal risks associated with these levels of radiation. A small increase in the relative risk of childhood cancer is suggested by a literature review of outcomes following low dose (less than 5 rads), in utero radiation exposure. With careful use of the available procedures, a diagnosis of venous thrombosis is possible with fetal radiation exposure of less than 0.50 rads and a diagnosis of pulmonary embolism is possible with fetal radiation exposure of less than 0.05 rads. The risk of such exposure is small, both in relative and absolute terms.