What is Mirena®? Mirena® is the brand name for the Levonorgestrel IUD (LNG-IUD). It is a T-shaped device, made of plastic with two fine nylon strings attached. The IUD sits in the uterus and the strings come through the cervix and sit against the wall of the upper vagina. Once in place you cannot feel the IUD in the uterus. You can feel inside the vagina to check these strings that tell you that the IUD is in place. The strings are also used to remove the IUD.