Comparison of continuation rates of intrauterine devices.

The validation of reports of the performance of intrauterine contraceptive devices (IUDs) is fraught with confounding factors such as different protocols, populations, and clinic environments. Two-year life table continuation rates from a comparative study of the Lippes loop, TCu-200, and Dalkon shield are reported from a single clinic in which 1626 insertions were performed by two obstetrician/gynecologists. The difference between the highest and lowest parity-standardized continuation rates for the three devices was only 3.7 percentage points after 2 years of use. The TCu-200 and Dalkon shield yielded significantly lower expulson rates than the Lippes loop. The more recently developed IUDs do not appear to have higher continuation rates than the Lippes loop.