Combined hormonal contraceptives and venous thromboembolism: putting the risks into perspective.

To date, 13 studies have provided data on the risk of venous thromboembolism associated with combined oral contraceptives containing drospirenone or the norelgestromin-containing contraceptive patch. The studies varied in their conclusions about whether these methods are associated with higher risks than combined oral contraceptives containing other progestins: the primary reported measures of association (adjusted odds ratios, incidence rate ratios, or hazard ratios) ranged from 0.9 to 3.3. All of the studies had weaknesses in population selection, data validity or completeness, or analysis that may have led to biased or spurious findings. Venous thromboembolism is rare; if the contraceptive methods of interest do confer a higher risk of thromboembolism, only an additional 5-10 per 10,000 users per year would be affected. The important message for patients, clinicians, and policy makers is that the benefits of all contraceptive methods markedly outweigh their risks, primarily because they prevent pregnancy, an inherently hazardous condition. Product labels for hormonal contraceptives should emphasize their substantial health benefits and established safety.