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 ethinylestradiol and levonorgestrel-containing birth control pills, and 10 to 15 per 10,000 women for birth control pills containing ethinylestradiol and a newer-generation progestin. 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. Risk of VTE with estrogen and progestogen therapy is highest at the start of treatment, particularly during the first year, and decreases over time. Older age, higher body weight, lower physical activity, and smoking are all associated with a higher risk of VTE with oral estrogen and progestogen therapy. Women with thrombophilia have a dramatically higher risk of VTE with estrogen and progestogen therapy than women without thrombophilia. Depending on the condition, risk of VTE can be increased as much as 50-fold in such women relative to non-use.