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Evaluation of: van Hylckama Vlieg A, Helmerhorst FM, Vandenbroucke JP, Doggen CJM, Rosendaal FR. The venous thrombotic risk of oral contraceptives, effects of oestrogen dose and progestogen type: results of the MEGA case–control study. BMJ 339, b2921 (2009).Women who use combined oral contraceptives containing estrogen and progestogen have an associated two- to eight-fold increased risk of venous thromboembolism. Over the years, in an attempt to reduce the associated venous thrombotic risk, newer preparations of oral contraceptives containing lower doses of estrogen and different types of progestogens have been introduced. The article under evaluation has quantified and further examined this association according to the dose of estrogen and the type of progestogen in oral contraceptives, in a large cohort of premenopausal women in The Netherlands. The results showed that oral contraceptive preparations that contain levonorgestrel and those that contain a low-dose estrogen were associated with lower risk than preparations containing other types of progestogens (including newer preparations, such as cyproterone acetate and drospirenone) and a greater estrogen dose, respectively.