A 2012 meta-analysis estimated that the absolute risk of VTE is 2 per 10,000 women for non-use, 8 per 10,000 women for EE and levonorgestrel-containing birth control pills, and 10 to 15 per 10,000 women for birth control pills containing EE and a third- or fourth-generation progestin such as desogestrel or drospirenone. For comparison, the absolute risk of VTE is generally estimated as 1 to 5 per 10,000 woman–years for non-use, 5 to 20 per 10,000 woman–years for pregnancy, and 40 to 65 per 10,000 woman–years for the postpartum period. Modern COCs are associated with about a 2- to 4-fold higher risk of VTE than non-use. The route of administration of EE does not appear to influence VTE risk, as EE/progestin-containing contraceptive vaginal rings and contraceptive patches have the same or even higher risk of VTE than COCs. Pregnancy is associated with about a 4.3-fold increase in risk of VTE. It has been estimated that at least 300 to 400 healthy young women die each year in the United States due to VTE caused by EE-containing birth control pills.