Progestogens when used by themselves at typical clinical dosages, for instance in progestogen-only birth control, do not affect coagulation and are not generally associated with a higher risk of venous thromboembolism (VTE). An exception is medroxyprogesterone acetate as a progestogen-only injectable contraceptive, which has been associated with a 2- to 4-fold increase in risk of VTE relative to other progestogens and non-use. The reasons for this are unknown, but the observations might be a statistical artifact of preferential prescription of depot medroxyprogesterone acetate to women at risk for VTE. Alternatively, medroxyprogesterone acetate may be an exception among progestogens in terms of influence on VTE risk, possibly due to its partial glucocorticoid activity. In contrast to depot medroxyprogesterone acetate, no increase in VTE risk has been observed with moderately high doses of the related progestin chlormadinone acetate (10 mg/day for 18–20 days/cycle), though based on limited data.