Study visits will occur on Days 3, 7, 14, and 21. Study entry will occur 2 to 6 days following the menses and within 30 days of screening. Medical and sexual history, a pelvic exam, cervicovaginal lavage sample collection, blood collection, vaginal pH testing, STI testing, and adverse effect reporting will occur at all visits. All participants will be asked to complete a diary throughout the study; this diary will be reviewed at all study visits. A Pap smear will be obtained at screening if documentation of a negative Pap smear result within the last year is not available.