Venous thromboembolism does not share strong familial susceptibility with pre‐eclampsia/eclampsia: a nationwide family study in S weden

Objective Genetic variants associated with venous thromboembolism ( VTE ) have been suggested to be involved in the pathogenesis of pre‐eclampsia/eclampsia ( PEC / EC ). This nationwide study aimed to determine whether VTE shares familial susceptibility with PEC / EC . Design Population‐based cohort study. Setting S weden. Sample A total of 941 841 S wedish women delivering their first child between 1987 and 2008. Methods Data from the S wedish M ultigeneration R egister were linked to the S wedish H ospital D ischarge R egister. The risk of PEC / EC was determined in primiparous women with a family history of VTE (in parents and/or siblings), compared with primiparous women without a family history of VTE . Odds ratios ( OR s) were calculated by logistic regression. Main outcome measure PEC / EC in first pregnancy. Results In total, 43 621 women had PEC / EC in association with their first pregnancy. The OR for PEC / EC in women with a family history of VTE was 1.06 (95%  CI 1.01–1.11); however, a family history of VTE was associated with higher odds of PEC / EC among women with previous hypertension ( OR  1.38, 95%  CI 1.25–1.52). Conclusion A family history of VTE is weakly associated with PEC / EC risk, and is not clinically useful for the prediction of PEC / EC . The results of the present study suggest that it is unlikely that strong disease‐causing mutations shared by VTE and PEC / EC are common in the S wedish population. The novel association between family history and PEC / EC among the subgroup with previous hypertension needs further confirmation in future studies.