LevonorgestrelIUD

Levonorgestrel-releasing intrauterine system (LNG-IUS) is a long-acting, reversible method of contraception. It is a small, T-shaped plastic device inserted into the uterus and designed to release levonorgestrel, a synthetic progestin, over several years. It is available under several brand names, including Mirena, Kyleena, Skyla, and Liletta.

Mechanism and effects: Levonorgestrel delivered locally thickens cervical mucus, inhibits endometrial growth, and may suppress ovulation in some cycles. The device is highly effective, with a very low failure rate in typical use. It also reduces menstrual bleeding, and many users experience lighter periods or amenorrhea. In addition to contraception, LNG-IUS is approved for the treatment of heavy menstrual bleeding and is sometimes used off-label for conditions such as endometriosis.

Duration, insertion, and safety: Depending on the product, the LNG-IUS remains in place for about 3 to 6 years (Skyla up to 3 years; Mirena and Kyleena up to 5 years; Liletta up to 6 years). Insertion requires a clinician and may cause discomfort; risks include device expulsion or uterine perforation. Common side effects include irregular bleeding in the first months, headaches, breast tenderness, or mood changes. It does not protect against sexually transmitted infections; barrier methods are advised if STI risk is present. Contraindications include pregnancy, known or suspected uterine abnormalities that would hinder placement, active pelvic infection, abnormal vaginal bleeding of unknown cause, and certain liver or breast cancers.