Effectiveness of the Diaphragm for HIV Prevention

Inclusion Criteria: * Age 18 to 49 years old * Sexually active (coital frequency at least four times per month on average) * HIV negative based on testing within two weeks prior to enrollment * Chlamydia trachomatis and Neisseria gonorrhoeae negative based on testing within 30 days prior to enrollment or if positive, completes treatment before enrollment * Have a healthy cervix, as assessed by naked-eye speculum exam at enrollment * Planning to live in the study area for the next 24 months * Willing to be randomly assigned either to use or not use a latex diaphragm with lubricant gel during participation in the study, and to follow the protocol, including being tested for HIV and STIs * Willing and able to give informed consent Exclusion Criteria: * Known sensitivity or allergy to latex * History of TSS (as suggested by current labeling for diaphragm use) * Currently pregnant, or desiring to become pregnant in the next two years * No cervix (total hysterectomy) * Refuses treatment for diagnosed or suspected current STI and/or reproductive tract infection requiring treatment at enrollment * Within six weeks of any pelvic surgery or last pregnancy outcome at the time of screening and enrollment * Presence of clinically apparent lesion(s) with epithelial disruption at enrollment (may enroll after lesion(s) has healed, if otherwise eligible) * Injected illicit drugs in the 12 months prior to screening and enrollment * Blood transfusion or received blood products in 3 months prior to screening and enrollment * Unable or unwilling to insert the diaphragm correctly * Participation in any other clinical trial (including those of a vaginal product or barrier contraceptive). Verification by comparing participant lists to other concurrently running research studies may be conducted if necessary. * Unable to speak English, Zulu, Shona, or Sotho * Other conditions that, in the opinion of the investigator, would constitute contraindications to participation in the study or would compromise ability to comply with the study protocol, such as a major psychiatric disorder