Efficacy and safety of a low-dose combined oral contraceptive containing drospirenone 3 mg and ethinylestradiol 20 mcg in a 24/4-day regimen

Objective: The study was conducted to assess the efficacy of a low-dose combined oral contraceptive (COC) containing drospirenone (drsp) 3 mg/ethinylestradiol (EE) 20 mcg administered for 24 days of active treatment followed by a 4-day hormone-free interval (24/4 regimen). Study Design: In this open-label uncontrolled study conducted in 50 European centers, healthy females aged 18-35 years with a body mass index of less than 30 kg/m(2) received drsp 3 mg/EE 20 mcg 24/4 over 13 cycles. The primary efficacy variable was the number of unintended pregnancies. Results: Five pregnancies occurred among 1101 women over 13,248 treatment cycles, resulting in a Pearl Index (PI) of 0.49 with an upper two-sided 95% CI limit of 1.14. Of these pregnancies, three were attributed to noncompliance with tablet use resulting in an adjusted PI for 'perfect use' of 0.22 (upper limit of two-sided 95%, CI: 0.80) based on 11,755 cycles. Conclusion: Drospirenone 3 mg/EE 20 mcg 24/4 is a highly effective COC in nonobese women. (C) 2009 Elsevier Inc. All rights reserved.