Lancet
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A multinational hospital-based case-control study of the risk of venous thromboembolic disease associated with combined oral contraceptives (OCs) done in 1989-93 prompted a separate inquiry comparing the risk of venous thromboembolism (VTE) associated with low oestrogen (< 35 micrograms ethinyloestradiol) OCs containing levonorgestrel with risks in low oestrogen preparations containing the third-generation progestagens desogestrel or gestodene. This analysis of data from 9 countries, involved 769 cases and 1979 age matched hospital controls and, in one centre, 246 community controls matched on age and general practice. 137 cases and 203 controls were current users of levonorgestrel (odds ratio [OR with 95% confidence interval] 3.5 [2.6-4.7]), with non-users as the reference; 35 cases and 28 controls were current users of desogestrel (9.1 [4.9-17.0]), and 36 cases and 28 controls were current users of gestodene (9.1 [4.9-16.7]). The ratios of these risks, compared with levonorgestrel, were 2.6 (1.4-4.8) for both products separately. ⋯ The possibility that these unexpected results on a secondary study objective are due to chance, bias, or residual confounding cannot be excluded entirely and the results need to be confirmed by independent studies. They are at variance with the apparently more favourable metabolic effects of the newer progestagens. Whether the new progestagens are associated with lower risk of arterial disease (stroke and myocardial infarction) must be evaluated further.
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Recent concern about the safety of combined oral contraceptives (OCs) with third-generation progestagens prompted an examination of data from a population-based case-control study (Leiden Thrombophilia Study). We compared the risk of deep-vein thrombosis (DVT) during use of the newest OCs, containing a third-generation progestagen, with the risk of "older" products. We also investigated the influence of family history of thrombosis, previous pregnancy, age, and the thrombogenic factor V Leiden mutation. ⋯ Use of low-dose OCs with a third-generation progestagen carries a higher risk of DVT than the previous generation of OCs. The absolute risk of DVT associated with these OCs seems to be especially high among carriers of the factor V Leiden mutation and among women with a family history of thrombosis. However, the higher risk associated with OC with a third-generation progestagen compared with previous generations was also present in women without factor V Leiden and with no family history.