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Evidence summaries

Risk of Venous Thromboembolism with the Use of Oral Contraceptives

An association between oral contraceptive use and venous thromboembolism (VTE) appears to exist, but the reported risk is probably exaggerated. The users of non-third-generation OCs have a less than 3-fold increase in risk for VTE compared to nonusers: the risk for VTE is possibly higher in users of third-generation OCs. Level of evidence: "B"

A systematic review 1, abstracted in DARE, assessed the risk of nonfatal venous thromboembolism (VTE) with oral contraceptive use (OC) (13 case-control studies, 3 retrospective cohort studies, 5 prospective cohort studies, and 1 RCT) and fatal VTE with OC use (2 case-control studies, 2 prospective cohort studies, 1 RCT). The pooled risk ratio for OC was 3.0 (95% CI 2.6 to 3.4) in case-control studies, 4.8 for retrospective cohort studies, 2.4 in prospective cohort studies, and 1.1 in RCTs. In users or third-generation OCs, the pooled risk ratio for VTE was 5.0 (95% CI 2.5 to 7.5).

Comment: The quality of evidence is upgraded by large magnitude of effect.

    References

    • Douketis JD, Ginsberg JS, Holbrook A, Crowther M, Duku EK, Burrows RF. A reevaluation of the risk for venous thromboembolism with the use of oral contraceptives and hormone replacement therapy. Arch Intern Med 1997 Jul 28;157(14):1522-30. [PubMed][DARE]

Primary/Secondary Keywords