Ethinyl estradiol/levonorgestrel/ferrous fumarate

This is a Phase 1, randomized, 2 way crossover, open-label study of the effect of multiple-dose PF 04965842 on single-dose OC PK in healthy female subjects. Subjects will be randomized to 1 of 2 treatment sequences. A total of 16 healthy female subjects (8 in each treatment sequence) will be enrolled in the study. Each treatment sequence will consist of 2 periods.

Women who have regular menstrual cycles have a lower risk of heart disease than men of the same age or women who no longer have menstrual cycles. The purpose of this study is to help determine why the menstrual cycle causes a lower risk of heart disease. The investigators believe that the hormones (estradiol and progesterone) produced during the menstrual cycle, as well as the normal processes occurring in the follicle and corpus luteum (transformed follicle), change levels of "good" and "bad" cholesterol in the blood-stream. These levels of good and bad cholesterol are an important risk factor for heart disease. Therefore, our goal is to determine what effects each of these factors (estradiol, progesterone, follicle, corpus luteum) have on the levels of good and bad cholesterol in the woman's bloodstream. As many women take birth control pills, which contain synthetic forms of estradiol and progesterone that block ovulation and development of a corpus luteum, the investigators also want to determine what effect one common type of birth control pill has on levels of good and bad cholesterol.