Mirena releases ____ of LNG per day.

Mirena contains a total of 52 mg levonorgestrel (LNG). LNG is released into the uterine cavity at a rate of approximately 20 microgram/day. The LNG IUD is about as effective as sterilization, but, unlike sterilization, it is easily reversible. These devices act mainly by local progestogenic effects and act for up to 5 years.