Objective: To assess the risk of venous thrombosis associated with nonoral contraceptives (ie, injectable depot-medroxyprogesterone acetate contraceptives, hormone [levonorgestrel]-releasing intrauterine devices, a contraceptive patch, or a contraceptive implant).
Methods and results: Analyses were performed in the Multiple Environmental and Genetic Assessment study, a large case-control study on risk factors for venous thrombosis. For the current analyses, we selected premenopausal women, aged 18 to 50 years, who were not pregnant nor within 4 weeks postpartum and were not using oral contraceptives; 446 patients and 1146 controls were included. Injectable depot-medroxyprogesterone acetate contraceptives were associated with a 3.6-fold (95% CI, 1.8- to 7.1-fold) increased risk of venous thrombosis compared with nonusers of hormonal contraceptives. The use of a levonorgestrel intrauterine device was not associated with an increased risk (odds ratio, 0.3; 95% CI, 0.1 to 1.1). Unfortunately, the few women using a contraceptive patch or an implant prevented a reliable estimate of the risk of thrombosis.
Conclusions: The risk of venous thrombosis was increased for injectable depot-medroxyprogesterone acetate contraceptive users, while we were able to reliably exclude an increased risk associated with levonorgestrel intrauterine device use. Therefore, the latter seems to be the safest option regarding the risk of venous thrombosis.