OBJECTIVE: to identify risk factors for venous thromboembolism (VTE) in the peripartum period and to provide guidelines for risk assessment and thromboprophylactic measures for VTE in pregnant women. Guidelines for diagnostic testing and for acute and long term treatment of VTE are also provided.OPTIONS: specific subgroups of pregnant women are defined and appropriate prophylactic measures are outlined. OUTCOMES: venous thromboembolism remains a major cause of morbidity and mortality in pregnancy and the postpartum period. Identification of risk and adequate prophylaxis can decrease the incidence of VTE.EVIDENCE: evidence was gathered using Medline (National Library of Medicine) to identify relevant studies and from bibliographies of articles thus identified.RECOMMENDATIONS: although evidence is lacking to date from Grade I studies (properly controlled randomized studies) in pregnant patients, there is good evidence to support the role of prophylaxis in reducing the incidence of VTE in patients identified to be at risk in the non-pregnant population (II B). Based on risk assessment more patients should be considered for thromboprophylaxis, including women with a past history of a VTE and a known thrombophilia on long-term anticoagulation, women with a past history of a VTE, women with a known thrombophilia who have never experienced a VTE and potentially considered in women at the time of Caesarean section (II B; III C). The occurrence of VTE is effectively reduced by the use of low dose unfractionated heparin. Experience with low molecular weight heparin and pregnancy is building, but is limited at present. Unfractionated heparin remains the standard for the treatment of VTE in pregnancy at the present time. Following initial heparinization for the treatment of VTE, patients should be continued on anticoagulation throughout pregnancy and for six to 12 weeks postpartum or a total of three months of anticoagulation (II A).