This contract provides support for a clinical trial whose overall objectives are: (1) to measure the ability of prophylactic antibiotics to reduce the risk of PID and other events requiring premature removal of the IUD, (2) to estimate incidence rates for PID and other events requiring IUD removal, and (3) to determine the side effects of the antibiotic used in the treatment. The investigation will be conducted in two parts: a preliminary study in which the protocol will be validated and the initial choice of antibiotic will be confirmed by microbiological studies of endometrial tissue for women requiring premature removal of their IUD, and a larger study in which the benefit of prophylactic antibiotics will be evaluated in a multi-center, randomized, double-blind study of 2000 women receiving an IUD as their choice for contraception. Study subjects will be obtained from the following sources for this study: Kaiser-Permanente Los Angeles, Kaiser-Permanente Woodland Hills, Planned Parenthood-World Population (Clinics at El Monte, Midtown Los Angeles, Santa Monica, and Sherman Oaks), and Los Angeles County Women's Hospital. The Contractor shall obtain information about the diagnosis and management of women who develop problems associated with IUD use that require removal of the device (subacute salpingitis, endometritis, endoparametritis, bleeding, or pelvic pain) and acquire information about participants who require treatment for acute pelvic inflammatory disease ()ID). The data collected shall be sufficient to determine whether the use of prophylactic antibiotics will be a valuable adjunct to the IUD-insertion procedure.