levonorgestrel-releasing intrauterine system

The levonorgestrel-releasing intrauterine system (LNG-IUS) is a long-acting reversible contraceptive (LARC) that provides highly effective pregnancy prevention for several years. Developed by Laboratorios Leon Farma, this specific system (marketed as Liletta in the US and Leosert in Europe) consists of a T-shaped polyethylene frame containing a reservoir of 52 mg of levonorgestrel, a synthetic progestin. The system releases levonorgestrel directly into the uterine cavity at an initial rate of approximately 20 mcg/day, which gradually decreases over time. Its primary mechanism of action involves thickening the cervical mucus to prevent sperm penetration, inhibiting sperm mobility and survival, and suppressing the endometrial lining to prevent implantation. In addition to contraception, it is approved for the treatment of heavy menstrual bleeding (menorrhagia), where it significantly reduces menstrual blood loss through its local effect on the endometrium.

Brand names

LilettaLeosertDonasertBenilexa

Other names

LNG-IUSlevonorgestrel intrauterine deviceLNG-IUD