Department of Obstetrics and Gynecology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina; and Duke Evidence-based Practice Center, Duke Clinical Research Institute, the Department of Community and Family Medicine, Doctor of Physical Therapy Division, and the Departments of Medicine, Obstetrics and Gynecology, and Biostatistics and Bioinformatics, Duke University School of Medicine, the Center for Health Services Research in Primary Care, Durham Veterans Affairs Medical Center, Duke Cancer Institute, Duke University Health System, and Duke Clinical Research Institute, Durham, North Carolina.
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OBJECTIVE:To estimate the risk of venous thromboembolism, stroke, or myocardial infarction (MI) associated with the use of oral contraceptive pills (OCPs) and to describe how these risks vary by dose or formulation.DATA SOURCES:We searched PubMed, Embase, the Cochrane Database of Systematic Reviews, and ClinicalTrials.gov for studies published from January 1995 through June 2012 that evaluated the association between OCP use and risk of venous thromboembolism, stroke, or MI.METHODS OF STUDY SELECTION:We reviewed 6,476 citations. We included English-language, controlled studies with human participants reporting a quantitative association between exposure to OCPs and outcomes of venous thromboembolism, stroke, or MI. Two investigators independently reviewed articles for inclusion or exclusion; discordant decisions were resolved by team review and consensus. Random-effects meta-analysis was used to generate summary odds ratios (ORs).TABULATION, INTEGRATION, AND RESULTS:Fifty studies met inclusion criteria. There were no randomized clinical trials. We found threefold increased odds of venous thromboembolism among current compared with noncurrent OCP users (14 studies; OR 2.97, 95% confidence interval [CI] 2.46–3.59). We found twofold increased odds of ischemic stroke (seven studies; OR 1.90, 95% CI 1.24–2.91). There was no evidence of increased risk of hemorrhagic stroke (four studies; OR 1.03, 95% CI 0.71–1.49) or MI (eight studies; OR 1.34, 95% CI 0.87–2.08).CONCLUSION:Current use of combined OCPs is associated with increased odds of venous thromboembolism and ischemic stroke but not hemorrhagic stroke or MI.