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In this device levonorgestrel is released directly in to the uterine cavity. The device has mainly a local and hormonal effect including thickening of cervical mucus, prevention of endometrial proliferation and, in some women, suppression of ovulation. The physical presence of the device also may have a minor contraceptive effect.

  • in comparison to copper intra-uterine contraceptive devices (IUCD)s, there is a lower risk of ectopic pregnancy and pelvic inflammatory disease. Also pre-existing menorrhagia may be alleviated. The risk of contraceptive failure is superior to that of copper IUCDs and similar to that of sterilisation (about 0.09 per 100 woman-years)
  • the Mirena system requires replacing only every five years (1,5)
  • the Mirena system can be inserted at any time between day 1 and 7 of the menstrual cycle, from 6 weeks post partum and at any time between day 1 and 5 after first-trimester abortion
  • in general, cautions and contra-indications are as for standard IUCDs
  • the product is also licensed as a treatment for "idiopathic menorrhagia", with the claim that it "may be particularly useful in women with idiopathic menorrhagia requiring (reversible) contraception" (2)
  • expulsion occurs in fewer than 1 in 20 women in five years (5)
  • IUS may act predominantly by preventing implantation and sometimes by preventing fertilisation (5)
  • no evidence of a delay in the return of fertility following removal or expulsion of the IUS (5)

Dose and frequency of administration (6):

  • One IUS to be inserted (after removal of previous IUS if required).
  • Insert on day 1-7 of the menstrual cycle with no need for additional protection
  • The IUS can be inserted at any time after day 7 of the menstrual cycle if it is reasonably certain that the individual is not pregnant. Additional contraception is then required for 7 days after insertion of the IUS.
  • For guidance on changing from one contraceptive method to another, and when to start after an abortion and postpartum, refer to the Faculty of Sexual and Reproductive Healthcare (FSRH) guidelines.

Frequency of IUS insertion:

  • Levonorgestrel 13.5mg IUS (Jaydess®) - effective for up to 3 years
  • Levonorgestrel 19.5mg intrauterine system (Kyleena®) - effective for up to 5 years.
  • Levonorgestrel 52mg Intrauterine System (Levosert ®) - effective for up to 6 years or until contraception no longer required if individual is over the age of 45 years of age at time of insertion
  • Levonorgestrel 52mg IUS (Mirena®) - effective for up to 5 years or until contraception no longer required if individual is over the age of 45 years of age at time of insertion.


  • the Levonorgestrel system is classified as an intra-uterine system (IUS) and not a IUCD


  1. Mimms, August 1998.
  2. Mirena. Summary of product characteristics, UK. Schering Health Care Ltd, February 2001
  3. Drug and Therapeutics Bulletin (2001);39 (11): 85-7.
  4. BNF 7.3
  5. NICE (September 2014). Long-acting reversible contraception
  6. Patient Group Direction (PGD) (NHS Specialist Pharmacy Service). Insertion of the Progestogen-Only Intra-Uterine System (IUS). (Accessed 17th March 2021).

Last edited 03/2021 and last reviewed 03/2021