Contraception in the chimpanzee: 12-year experience at the CIRMF Primate Centre, Gabon

The Primate Centre of the International Center for Medical Research in Franceville, Gabon (CIRMF) has had a chimpanzee (Pan troglodytes) colony for more than 20 years. A contraceptive policy was started in 1990, following a rapid increase in the number of individuals in the 1980s. Intrauterine devices were first used in 24 females; 10 failures occurred over a period of about 4 years. Depo-provera was then used in 28 chimpanzees for between 4 months and 4 years; 10 failures occurred, the animals gained weight, and cyclic swelling of the external genitalia was markedly modified. Starting in late 2000, 25 females received progestin implants; only one failure has so far occurred, and the main side effect is a complete abrogation of cyclic sexual swelling.