Int J Gynaecol Obstet

BackgroundCombined oral contraceptives (COCs) containing various progestogens could be associated with differential risks for venous thromboembolism (VTE).ObjectiveTo evaluate the comparative risks of VTE associated with the use of low\u2010dose (less than 50\ua0\u3bcg ethinyl estradiol) COCs containing different progestogens.Search strategyPubMed and the Cochrane Library were searched from database inception through September 15, 2016, by combining search terms for oral contraception and venous thrombosis.Selection criteriaStudies reporting VTE risk estimates among healthy users of progestogen\u2010containing low\u2010dose COCs were included.Data collection and analysisA random\u2010effects model was used to generate pooled adjusted risk ratios and 95% confidence intervals; subgroup and sensitivity analyses assessed the impact of monophasic\u2010COC use and study\u2010level characteristics.Main resultsThere were 22 articles included in the analysis. The use of COCs containing cyproterone acetate, desogestrel, drospirenone, or gestodene was associated with a significantly increased risk of VTE compared with the use of levonorgestrel\u2010containing COCs (pooled risk ratios 1.5\u20132.0). The analysis restricted to monophasic COC formulations with 30\ua0\u3bcg of ethinyl estradiol yielded similar findings. After adjustment for study characteristics, the risk estimates were slightly attenuated.ConclusionsCompared with the use of levonorgestrel\u2010containing COCs, the use of COCs containing other progestogens could be associated with a small increase in risk for VTE.001/World Health Organization/International29388678PMC596930