DESCRIPTION (Adapted from applicant's description): The applicant proposes a Pilot Study to assess the feasibility of a randomized controlled trial comparing the incidence of pelvic inflammatory disease (PID) in users of copper intrauterine devices (IUDs) to the incidence in users of injectable depotmedroxyprogesterone acetate (DMPA). If indicated by the Pilot Study, the applicant will propose a larger Main Clinical Trial to measure and compare the PID risks of the IUD and DMPA more accurately. Pilot Study specific aims are: to determine the feasibility of enrolling and randomly assigning family planning acceptors to IUD or DMPA use; to collect information on the suitability of our four participating sites for a subsequent Main Clinical Trial, including: baseline prevalence of cervical gonorrhea and chlamydia among 100 study participants randomized to IUD or DMPA use; baseline prevalence of cervical gonorrhea and chlamydia among 100 non-participating IUD and DMPA users at each study site, to increase the precision of the estimates; cumulative probability of PID among Pilot Study participants during follow-up; adequacy of clinic facilities and staff, especially with regard to the diagnosis of PID. Women at each site who are willing to initiate either IUD or DMPA use and are medically eligible for both will be approached. Each woman will be counseled and screened as envisioned for the Main Trial. Eligible women will receive the assigned method according to computer-generated random assignment cards in sealed opaque envelopes. Participants will be followed for up to twelve months each with visits scheduled at two weeks, one, three, six, nine and twelve months after enrollment. PID will be diagnosed according to two separate standards: a sensitive one designed to ascertain the maximum number of cases accepting some over-treatment; and a specific one that is more congruent with U.S. clinical definition and practice. Criteria for determining the feasibility of the Main Clinical Trial include: The applicant must succeed in randomizing, enrolling and following close to 400 women combined within nine months. The applicant must detect evidence of moderate STD prevalence and PID incidence in the cohorts.