Intrauterine devices

Abstract

The main benefits of IUDs are a high level of effectiveness, lack of associated systemic metabolic effecs, a single act of motivation required for long-term use. In contrast to other types of contraception, there is no need for the constant motivation needed to ingest a pill daily or to use a coitus-related method consistently. These characteristics, as well as the fact that a visit to a health-care facility is required for discontinuing the method, account for the fact that IUDs have the highest continuation rate of all currently available reversible methods of contraception. Of course it is desirable for all women to make at least annual visits to a health-care facility, but in some areas of the world this is not possible. Unlike other contraceptive methods, such as barrier techniques, which rely on use by the acceptor and have higher use-failure rates than method-failure rates, the method-effectiveness and use-effectiveness rates for IUDs are similar. First-year failure rates are generally reported to range from 2 to 3 per cent; however, pregnancy rates are related to the skill of the inserting clinician. With experience correct high fundal insertion occurs more frequently, and there is a lower incidence of partial or complete expulsion, with resultant lower pregnancy rates. Furthermore, the annual incidence of accidental pregnancy decreases steadily after the first year of IUD use. After six years of use of the loop, the cumulative failure rate is less than 1 per cent per year. In addition, the incidence of all major adverse events with IUDs, including pregnancy, as well as expulsion or removal for bleeding and/or pain, steadily decreases with increasing age, and women over 35 have pregnancy rates less than 2 per cent in the first two years of use of the loop. Thus, the IUD is especially suited for older parous women who wish to prevent further pregnancies.