Contraception and the prevention of sexually transmitted diseases.

Sexually transmitted diseases (STDs) are a major cause of ill health in women and their sexual partners and children. Contraceptive methods alter in various ways the risk of acquiring STD but assessment of the odds ratio is difficult due to the many confounding factors. Spermicides have been reported to kill a wide range of bacteria and viruses including HIV in vitro and to protect in vivo from infection by gonorrhoea, chlamydia and pelvic inflammatory disease (organisms unspecified). Spermicides will not cure pre-existing infections. Condoms and diaphragms will give some protection from bacterial and viral infections in all parts of the genital tract. Hormonal contraception and tubal ligation give protection to the upper genital tract but not the cervix. Carcinoma of the cervix follows the same pattern as STDs. The risk of pelvic infection in intrauterine device users is discussed in the chapter by Bromham (pp 100-123, this issue).