Postcoital Testing Study of the SILCS Diaphragm Used With 3% N-9 Gel, ContraGel, or No Gel

Inclusion Criteria: 1. Age 18-45 years, inclusive 2. General good health, by volunteer history and per investigator judgment 3. History of regular menstrual cycles of 24-35 days (inclusive), by volunteer report 4. History of Pap smears and follow-up consistent with standard medical practice as outlined in the Study Manual or willing to undergo a Pap smear at Visit 1 5. Willing to abstain from intercourse and use of vaginal products as required in the protocol 6. Willing to use non-spermicidal, lubricated condoms from the first day of each menstrual cycle until 72 hours before expected midcycle 7. In a mutually monogamous relationship for at least the last four months with a male partner who: 7a. Is at least 18 years old; 7b. Has no known risk for STIs; 7c. Is willing and able to comply with protocol requirements including sexual activity/ abstinence and condom use requirements; and 7d. Can engage in vaginal intercourse with the participant, with and without condoms, as specified in protocol 8. Protected from pregnancy by female tubal sterilization 9. Vaginal and cervical anatomy that, in the opinion of the investigator, lends itself to easy genital tract sample collection 10. Willing to give voluntary consent, sign an informed consent form and comply with study procedures as required by the protocol Exclusion Criteria: 1. History of hysterectomy 2. Vasectomy in male partner 3. Sterility or known history of sperm dysfunction in male partner 4. Currently pregnant or within two calendar months from the last pregnancy outcome. Note: If recently pregnant must have had at least two spontaneous menses since pregnancy outcome 5. Current use of any hormonal contraceptive or a copper IUD, or use of Depo-Provera in the last 120 days 6. Currently breastfeeding or having breastfed an infant in the last two months, or planning to breastfeed during the course of the study 7. Significant gynecological abnormalities (including abnormal vaginal bleeding or excessive vaginal discharge) 8. Device does not appropriately fit volunteer, as determined by clinician 9. Inability to insert, position, and/or remove study device, by clinician or volunteer 10. History of sensitivity/allergy to 3% N-9, latex, ingredients in ContraGel, or silicone, for either the volunteer or her male partner 11. In the last six months, either the volunteer or her male partner diagnosed with or treated for any STI or pelvic inflammatory disease. Note: Women with a history of genital herpes or condylomata who have been asymptomatic for at least six months may be considered for eligibility 12. Positive test for Trichomonas vaginalis, Neisseria gonorrhea or Chlamydia trachomatis 13. Deep epithelial genital findings such as abrasions, ulcerations, and lacerations, or vesicles suspicious for a sexually transmitted infection 14. Positive test for HIV 15. Chronic or acute vulvar or vaginal symptoms (pain, irritation, spotting, etc.) 16. Known current drug or alcohol abuse which could impact study compliance 17. Participation in any other investigational trial within the last 30 days or planned participation in any other investigational trial during the study 18. History of gynecological procedures (including genital piercing) on the external genitalia, vagina or cervix within the last 14 days 19. Abnormal finding on laboratory or physical examination or a social or medical condition in either the volunteer or her male partner which, in the opinion of the investigator, would make participation in the study unsafe or would complicate interpretation of data