Unadjusted First-year and 3-year Pearl Indices According to Age, Parity Status and BMI (Full Analysis Set).

* Relevant exposure was calculated from the total exposure minus the time in which back-up contraception was used or sex hormones were taken for other reasons.BMI, body mass index; CI, confidence interval; WY, woman-year (1 WY = 365 days); LNG-IUS 8; levonorgestrel intrauterine system total content 13.5 mg (average approx. 8 μg/24 hours over the first year); LNG-IUS 13, levonorgestrel intrauterine system total content 19.5 mg (average approx. 13 μg/24 hours over the first year).Unadjusted First-year and 3-year Pearl Indices According to Age, Parity Status and BMI (Full Analysis Set).