Additional Study Information: If you are a woman between the ages of 18 and 35, are pre-menopausal, sexually active and do NOT wish to become pregnant, you are invited to see if you may qualify for a research study. The purpose of this research study is to test the effectiveness of an investigational oral birth control pill. If you qualify, you will receive investigational study medication, study-related medical exams, and laboratory services at no charge. You may also be reimbursed for time, travel, and other expenses.