Levonorgestrel-Releasing Intrauterine System

Levonorgestrel-releasing intrauterine system is a type of contraceptive used to help prevent pregnancy for up to five years. This device is inserted into the uterus and slowly releases a hormone that alters the cervical mucus, changes the lining of the uterus, and has other effects. Adverse reactions are possible and may include acne, ovarian cysts, and vaginal infections.

What Is Levonorgestrel-Releasing Intrauterine System?

Levonorgestrel-releasing intrauterine system (Mirena®, Skyla™) is a prescription intrauterine contraceptive (IUC, also called an intrauterine device, or IUD) that is placed into the uterus, where it slowly releases levonorgestrel. Levonorgestrel is a progesterone hormone found in several birth control pills.
The device is a small, flexible, T-shaped product made from plastic. It can remain in the uterus for three to five years, depending on the actual product used, and prevents pregnancy for that entire period. This can be an advantage for women who desire long-term birth control.
There are currently two available levonorgestrel-releasing intrauterine devices on the market in the United States: Mirena and Skyla. Mirena is approved to provide birth control for up to five years. It is best for women who have already had at least one child. Mirena is also approved to treat heavy menstrual bleeding in women who want an IUD to prevent pregnancy.
Skyla, the other levonorgestrel-releasing IUD, is approved to prevent pregnancy for up to three years. It is slightly smaller in size than Mirena and can be used in women who have not yet had a baby.
Of note, ParaGard® (the copper IUD) is another IUD available in the United States. ParaGard is hormone-free. It is approved to provide birth control for up to 10 years.
(Click What Is Levonorgestrel-Releasing Intrauterine System Used For? for more information on this topic, including possible off-label uses.)
Last reviewed by: Kristi Monson, PharmD
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