You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is What is the rate of release of levonorgestrel into the uterus from Mirena, a progestin releasing intrauterine device? and explain in detail?
Mirena is a progestin releasing device, it releases levonorgestrel into the uterus at a rate of 20 microgm/d. It has a T-shaped radiopaque frame, with its stem wrapped with a cylinder reservoir, composed of a polydimethylsiloxane-levonorgestrel mixture. Cu T 380A is another progestin releasing device. It has a polyethylene and barium sulfate, T-shaped frame wound with copper. Ref: Cunningham F.G., Leveno K.J., Bloom S.L., Hauth J.C., Rouse D.J., Spong C.Y. (2010). Chapter 32. Contraception.