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ABO blood groups and risk of venous thromboembolism during pregnancy and the puerperium. A population‐based, nested case–control study
Author(s) -
LARSEN T. B.,
JOHNSEN S. P.,
GISLUM M.,
MØLLER C. A. I.,
LARSEN H.,
SØRENSEN H. T.
Publication year - 2005
Publication title -
journal of thrombosis and haemostasis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.947
H-Index - 178
eISSN - 1538-7836
pISSN - 1538-7933
DOI - 10.1111/j.1538-7836.2005.01195.x
Subject(s) - medicine , abo blood group system , odds ratio , nested case control study , obstetrics , pregnancy , confidence interval , pulmonary embolism , population , case control study , confounding , attributable risk , relative risk , gynecology , genetics , environmental health , biology
Summary. Objectives: To examine possible associations of ABO blood types with the risk of venous thromboembolism (VTE) in pregnancy and the puerperium. Patients and methods: We conducted a nested case–control study within a cohort of 71 729 women who gave birth to 126 783 children in the North Jutland County, Denmark, from 1980 to 2001. We identified 129 cases with VTE in pregnancy ( n = 61) or the puerperium ( n = 68), and 258 controls with no VTE. We collected information on ABO blood groups and possible maternal confounding factors and estimated the relative risk [odds ratio (OR)]. Results: Women with an A or AB blood group had elevated risk estimates of VTE in pregnancy or the puerperium compared with women with a O blood group [adjusted ORs 2.4, 95% confidence interval (CI) 1.3, 4.3, and 2.0, 95% CI 0.7, 5.8, respectively]. No increased risk estimate was found for group B (adjusted OR 1.2, 95% CI 0.5, 3.0). The increased risk estimates of VTE for blood groups A and AB appeared present in both pregnancy (adjusted ORs of 3.9, 95% CI 1.5, 9.7, and 2.2, 95% CI 0.4, 12.5) and in the puerperium (adjusted ORs of 2.4, 95% CI 1.0, 4.9 and 2.7, 95% CI 0.8, 9.3). Furthermore, blood groups A and AB appeared to be associated with increased risk estimates for both DVT and pulmonary embolism. Conclusion: Keeping the modest statistical precision of our study in mind, blood groups A and AB may be associated with increased risk estimates for VTE in pregnancy and the puerperium.