Pregnancy-Related Venous Thromboembolism Risk in Asymptomatic Women With Antithrombin Deficiency: A Systematic Review.

<bold>Objective: </bold>To evaluate the risk of pregnancy-associated venous thromboembolism in women with asymptomatic antithrombin deficiency.<bold>Data Sources: </bold>The search was performed on MEDLINE (Ovid and PubMed databases) for the period 1966 to June 2012 and ClinicalTrials.gov as of December 15, 2015.<bold>Methods Of Study Selection: </bold>A systematic review including randomized controlled trials, cohort studies, and case-control studies was conducted. Selection criteria included objectively diagnosed venous thromboembolism or venous thromboembolism treated with 3 months of anticoagulation before the availability of objective testing. The study population consisted of pregnant women with asymptomatic antithrombin deficiency.<bold>Tabulation, Integration, and Results: </bold>Seven publications were included in the review. No randomized controlled trials were identified. The best available data consist of three retrospective cohort studies and four case-control studies. Pooled results from case-control studies yielded an estimated odds ratio for venous thromboembolism of 6.09 (95% confidence interval 1.58-23.43). No pooled estimates could be obtained for cohort studies. Data on use of thromboprophylaxis were scarce.<bold>Conclusion: </bold>Despite the small number of patients included, and the variation in study designs, pooled results from case-control studies show a significant association between asymptomatic antithrombin deficiency and pregnancy-associated venous thromboembolism. Thromboprophylaxis during pregnancy and postpartum should be considered in these women. [ABSTRACT FROM AUTHOR]