OBJECTIVES: Compare pregnancy rates post-initiation of 84/7 (84 days levonorgestrel/ethinyl estradiol (EE) 0.15mg/0.03mg tablets plus EE 0.01mg or placebo for 7 days or 84 days levonorgestrel/ethinyl estradiol [EE] 0.1mg/0.02mg tablets plus EE 0.01mg for 7 days) to use of 21/7 (21 days combined EE/progestin plus 7 days placebo) or 24/4 (24  days EE/progestin plus 4 days placebo) oral contraceptive regimens over the course of 1 year. METHODS: Data for this study were obtained from the US i3 InVisionTM database from January 1, 2006 through December 31, 2011. Patients were included if they received the medication of interest (with first such receipt identified as index date), were age 15-40 on index date, and had continuous insurance coverage from index date through 1 year post index date. Two distinct analyses were performed: 1 comparing pregnancy rates post-initiation on a 84/7 or 21/7 OC and the other comparing pregnancy post-initiation on a 84/7 or 24/4 OC. The 84/7 cohort was matched to each of the alternative cohorts of interest based upon age, sex, region, business type of insurance, insurance product and year of index date. RESULTS: There were 29,532 individuals in the 84/7 cohort, 662,721 individuals in the 21/7 cohort, and 169,871 individuals in the 24/4 cohort. Matching of the 84/7 cohort to each of the alternative cohorts resulted in a successful match rate of over 99% when comparing 84/7 with 21/7 and 96.7% when comparing 84/7 with 24/4. Pregnancy rates in the 1 year post-initiation on an OC were statistically significantly lower for initiators of 84/7 compared with 21/7 (7.52% v 4.43%; P<0.0001) as well as when comparing 84/7 with 24/4 (6.95% v 4.43%; P<0.0001). CONCLUSIONS: In this study, pregnancy rates were significantly lower in women using a 84/7 OC regimen compared with 21/7 or 24/4 regimens.