Levonorgestrel Intrauterine System

How it works

Locally released levonorgestrel thickens cervical mucus, suppresses endometrial proliferation, and in some women inhibits ovulation.

Prescribing in practice

• Exclude pregnancy and current pelvic infection before insertion, and counsel that it does not protect against sexually transmitted infections.
• It is a first-line option for heavy menstrual bleeding and provides endometrial protection in women taking oestrogen.
• Avoid in current breast cancer, undiagnosed vaginal bleeding, active pelvic infection, and significant active hepatic disease.

Monitoring

Review a few weeks after insertion to confirm correct placement and exclude infection or expulsion, then periodically as clinically appropriate.

Counselling the patient

• Irregular bleeding or spotting is common at first and usually settles, with many women eventually having very light or absent periods.
• Seek review if you develop severe pelvic pain, abnormal discharge or fever, or cannot feel the threads.
• Remember it does not protect against sexually transmitted infections.

Evidence & guidelines

NICE guidance on heavy menstrual bleeding (NG88) recommends the levonorgestrel intrauterine system as a first-line treatment option.