- any intrauterine device (IUD) with published data showing that the highest expected failure rate is less than 1% per year. Acceptable IUDs, for the purposes of this study, include TCu-380A (Paragard), TCU-380 Slimline (Gyne T Slimline), MULTILOAD-250 (MLCu-250) and 375, Levonorgesterol LNG-20 Intrauterine System (Mirena/Levonova), and Flexigard 330/CuFix PP330 (Gynefix).The subject must have had the device inserted at least 2 weeks prior to Screening, throughout the study, and 2 weeks following the discontinuation of Investigational Product.