The levonorgestrel intrauterine system (LNG IUS) is a T-shaped plastic device placed in the uterus that steadily releases small amounts of levonorgestrel each day. The T-body adjusts the system to the shape of the uterus and the vertical arm of the T-body carries the drug reservoir containing the hormone. Two threads are tied to the system which exit from the cervix to allow the user to ensure its presence and assist in its removal. Levonorgestrel is the progestin hormone released from the IUS, provided locally in the uterus, at a steady dose for up to five years.
LNG IUS functions by:
Additional to the protection against pregnancy, there are additional health benefits associated with use of LNG IUS. These benefits may include the reduction of iron-deficiency anemia and the lessening of menstrual cramps and symptoms of endometriosis. LNG IUS is also proven to reduce heavy periods, menorrhagia, in women who choose intrauterine contraception.
- Thickening the mucus in the cervix so that sperm cannot get through to fertilize the egg.
- Keeping the lining of the uterus (endometrium) thin.
- Reducing the motility of sperm so that they are less likely to reach or fertilize the egg.
- Preventing ovulation in some women during some cycles.