Levonorgestrel-releasing (20 microgram/day) intrauterine systems (Mirena) compared with other methods of reversible contraceptives

BJOG. 2000 Oct;107(10):1218-25. doi: 10.1111/j.1471-0528.2000.tb11610.x.


Objective: To assess the relative contraceptive effectiveness, tolerability and acceptability of the levonorgestrel-releasing (20 microg per day) intrauterine system (LNG-20) compared with reversible contraceptive methods in women of reproductive age.

Design: A systematic review and meta-analysis of randomised controlled trials.

Identification: Studies were identified through seven databases, and by contacting investigators and organisations working in the contraceptive field.

Main outcome measures: Unplanned pregnancy and continuation of contraceptive method.

Results: Five of the seven randomised controlled trials which met the inclusion criteria were included in the meta-analyses; four were comparisons of the LNG-20 intrauterine system with nonhormonal intrauterine devices. LNG-20 intrauterine systems were compared with intrauterine devices divided into two categories, those > 250 mm3 (Copper T 380 Ag and Copper T 380A intrauterine devices) and those < or = 250 mm3 (Nova-T, Copper T 220C and Copper 200 intrauterine devices). Pregnancy rates for the LNG-20 intrauterine system users were significantly less likely to become pregnant compared with users of intrauterine devices < or = 250 mm3, and significantly less likely to have an ectopic pregnancy. LNG-20 intrauterine system users were more likely to experience amenorrhoea and device expulsion than women using intrauterine devices > 250 mm3. LNG-20 intrauterine system users were significantly more likely than all the intrauterine device users to discontinue because of hormonal side effects and amenorrhoea. When the LNG-20 intrauterine system was compared with Norplant-2, the LNG-20 users were significantly more likely to experience oligo-amenorrhoea, but significantly less likely to experience prolonged bleeding and spotting.

Conclusions: The effectiveness of the LNG-20 intrauterine system was similar to or better than other contraceptive methods with which it was compared. Amenorrhoea was the main reason for the discontinuation of the LNG-20 intrauterine system, usually unnecessarily, since this end-organ suppression of bleeding is benign, associated with normal oestrogen levels. Women choosing this method should be informed of potential amenorrhoea when having pre-contraceptive counselling and that absent bleeding may be viewed as a positive outcome.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Review
  • Systematic Review

MeSH terms

  • Contraception / methods*
  • Contraceptive Agents, Female / administration & dosage*
  • Contraceptive Agents, Female / adverse effects
  • Counseling
  • Female
  • Humans
  • Intrauterine Devices, Medicated*
  • Levonorgestrel / administration & dosage*
  • Levonorgestrel / adverse effects
  • Menstruation Disturbances / chemically induced
  • Meta-Analysis as Topic
  • Randomized Controlled Trials as Topic
  • Risk Factors


  • Contraceptive Agents, Female
  • Levonorgestrel