CONTENTS
HIGHLIGHTS
December 1995 |
The IUD is one of the most effective methods of contraception. With most devices, pregnancy rates range from less than one to three per 100 women per year. Among widely used copper IUDs, three are most effective—the TCu-380A, TCu-220C, and MLCu-375, with the TCu-380A being the most effective of these. Pregnancy rates for all major IUDs are less than one per 100 women per year (see Table 1). They are at least as effective as Norplant® implants, injectable contraceptives, and voluntary male or female sterilization (331, 547). In an ongoing international comparative trial sponsored by WHO, after 10 years of use the cumulative pregnancy rate for the TCu-380A was 2.1 per 100 women and for the TCu-220C was 5.7 (625). This difference is statistically significant. For the LNG-20 a pregnancy rate of 0.3 has been reported after five years of use (573). Pregnancy rates for earlier devices—the TCu-200, the Cu-7, and the Lippes Loop—are about 2 per 100 women in the first year (331) (see Table 1). The stainless steel ring, widely used in China through the early 1900s, was less effective, with pregnancy rates as high as 10 per 100 women at two years (363, 364, 603). A 1982 survey found that 34% of induced abortions in China followed IUD failures (66). Analysis showed that more effective IUDs would reduce health risks and save the Chinese government substantial costs (603). Beginning in 1993 the Chinese government switched to supplying only copper-bearing IUDs to family planning providers (570, 632). Like most other reversible contraceptives, the IUD is thought to perform less well in general use than in clinical trials (387, 505). Still, in practice it remains one of the most effective reversible contraceptive methods. According to data from Demographic and Health Surveys in 15 countries, for example, the pregnancy rate with various IUDs was 3.4 per 100 IUD users in the first year of use, 5.9 per 100 oral contraceptive users, 12.5 for withdrawal, and 19.9 for rhythm (533). An earlier analysis of World Fertility Survey data in five Latin American countries placed the pregnancy rate for condoms at 18 per 100 (122). A 1980 Philippine survey also reported markedly lower pregnancy rates among IUD users than among oral contraceptive users (204). In three provinces of Vietnam a retrospective study reported a pregnancy rate of about 3% in the first year of use among women whose IUDs remained in place (584). |