Additional Study Information: The purpose of this study is to assess the effectiveness of AG200-15 which is an investigational birth control patch. AG200-15 is an investigational birth control patch being developed for use by women who wish to use a skin patch to prevent pregnancy. It contains LNG (levonorgestral) and EE (ethinyl estradiol), which are female sex hormones and are active ingredients in some approved birth control pills. The drugs contained in the patch are absorbed through the skin. All participants in the study will receive patches containing LNG and EE; there is no placebo (patch without hormones) or birth control pill being used in the study. The patch is used in a 4-week (28 day) treatment cycle where a patch is applied and replaced every 7 days for 3 weeks in a row, followed by a 1-week "patch-free" period.