Risk factors for pregnancy-associated venous thromboembolism: a review

To critically evaluate current understanding of risk factors for pregnancy-associated venous thromboembolism (VTE) and to describe underlying molecular mechanisms.

A literature search was undertaken using the national library of medicine PubMed database. The search terms used were "pregnancy" and "venous thromboembolism". Following exclusion of unsuitable data sources, studies were identified that described specific risk factors for pregnancy-associated VTE and suggested possible underlying molecular mechanisms. Adjusted odds ratios and incident rate ratios for these specific risk factors were identified in each study and tabulated.

A series of mainly retrospective cohort and case control studies over the past two decades have reported specific risk factors for pregnancy-associated VTE. Recent published literature has highlighted the interaction between commonly occurring risk factors, particularly the potential for a multiplicative effect on overall VTE risk, and have led to improvements in our understanding of the molecular mechanisms underlying these risk factors.

Mortality from pregnancy associated VTE continues despite prevention strategies. A detailed understanding of specific risk factors, their interactions and underlying molecular mechanisms is required to identify women at highest risk and to guide development of thromboprophylaxis strategies.