Objective: To assess the efficacy and safety of Seasonique (TM), a 91-day extended-regimen oral contraceptive (OC) utilizing continuous low-dose ethinyl estradiol (EE) during the typical hormone-free interval. Methods: A multicenter, open-label, 1-year study of Seasonique (TM) [30 mu g EE/150 mu g levonorgestrel (LNG)] for 84 days followed by EE 10 mu g for 7 days was conducted in sexually active, adult women of childbearing potential. All patients completed daily electronic diaries to monitor compliance and bleeding. Results: Method failure rate was 0.78 (Pearl index) and 0.64% (life table analysis). Cycle control and safety of the regimen were similar to that reported for other OCs. Conclusion: This study demonstrates that Seasonique (TM) is effective, safe and well tolerated for the prevention of pregnancy. (c) 2006 Elsevier Inc. All rights reserved.