Mirena

Mirena is a brand of intrauterine device (IUD) that releases the progestin levonorgestrel. It is a small, flexible, T-shaped device placed in the uterus by a trained clinician. It contains about 52 mg of levonorgestrel and provides long-acting contraception for up to five years in eligible users. In addition to preventing pregnancy, Mirena is approved in some regions to reduce heavy menstrual bleeding in women who desire contraception.

Mechanism of action: Mirena releases levonorgestrel locally within the uterus. The hormone thickens cervical mucus, which hinders sperm movement, and it thins and stabilizes the endometrium, often reducing or stopping menstrual bleeding. Systemic hormone exposure is relatively low compared with many other hormonal methods.

Usage and effectiveness: Mirena is more than 99% effective at preventing pregnancy with typical use. It is a long-acting reversible contraception, meaning it does not require daily action after insertion. If used as an approved treatment for heavy menstrual bleeding, it can substantially reduce menstrual blood loss for many users.

Insertion and considerations: Insertion is performed during a clinic visit and may cause cramping, dizziness, or discomfort. The device has a withdrawal string that remains in the vagina to indicate placement. Expulsion or malposition can occur, especially in the first year. If pregnancy occurs with Mirena in place, there is an increased risk of ectopic pregnancy.

Safety and contraindications: Mirena should not be used during known pregnancy or in the presence of undiagnosed vaginal bleeding, active pelvic infection, or uterine anomalies that distort the cavity. Other contraindications include liver disease, breast cancer, and hypersensitivity to levonorgestrel or device components.