Pelvic inflammatory disease in intrauterine device users

Pelvic inflammatory disease (PID) has been associated with the use of intrauterine devices (IUDs) ever since they were introduced. In several mostly retrospective studies the incidence of PID was suggested to be as high as three- to ninefold in IUD users compared to non-users. Later epidemiological prospective studies showed a considerably lower risk comparing different types of contraception. Compared to non-contraceptive users the relative risk ranged from 1.8 in patients with copper-containing IUDs to 3.3 in patients using the older insert IUDs like the Dalkon Shield. More recent studies indicate that PID among IUD users is strongly related to the insertion process and to background risk of sexually transmissible disease. The incidence rate of PID decreases from 9.66 per 1000 woman years during the first 20 days following insertion to 1.38 per 1000 woman years beyond the first 20 days. This incidence is similar to the incidence in non-IUD users. PID is more prevalent in younger single women with different sexual partners. Nulliparous women with stable monogamous relationships are not at higher risk of PID than parous women. In conclusion, IUD users, selected for low risk of sexually transmissible disease, do not have excess PID. Proper counselling and selection is of the utmost importance. As there is a higher risk shortly after insertion, limiting IUD replacements will help diminish PID incidence.