Comparison of the Lippes Loop D and tapered Lippes Loop D intrauterine devices.

The tapered Lippes Loop D (LLD) is compared to the standard LLD to evaluate efficacy and termination events. The tapered device was designed with the intention of lowering the expulsion rate below the rate for women with standard Lippes Loops. The two devices were randomly assigned to 989 women in two studies. Expulsion rates for the tapered device were lower at six months (p less than 0.10) and at 12 months (p less than 0.05). When the women were divided into groups by uterine measurement, the differences continued to be significant for women with larger uteri but not for those with smaller uteri. Comparison of other pertinent event rates showed no significant differences. Analysis of the data indicates that the tapered LLD represents an improvement in expulsion rates over the standard LLD.