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

Objective To assess the relative contraceptive effectiveness, tolerability and acceptability of the levonorgestrel-releasing (20 mu g per day) intraut erine system (LNG-20) compared with reversible contraceptive methods in wom en of reproductive age. Design A systematic review and meta-analysis of randomised controlled trial s. Identification Studies were identified through seven databases, and by cont acting 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 inclus ion criteria were included in the meta-analyses; four were comparisons of t he LNG-20 intrauterine system with nonhormonal intrauterine devices. LNG-20 intrauterine systems were compared with intrauterine devices divided into two categories, those > 250 mm(3) (Copper T 380 Ag and Copper T 380A intrau terine devices) and those less than or equal to 250 mm(3) (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 less than or equal to 250 mm(3 ), and significantly less likely to have an ectopic pregnancy. LNG-20 intra uterine system users were more Likely to experience amenorrhoea and device expulsion than women using intrauterine devices > 250 mm(3). LNG-20 intraut erine system users were significantly more likely than all the intrauterine device users to discontinue because of hormonal side effects and amenorrho ea. When the LNG-20 intrauterine system was compared with Norplant-2, the L NG-20 users were significantly more likely to experience oligo-amenorrhoea, but significantly less likely to experience prolonged bleeding and spottin g. 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 intra uterine 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-co ntraceptive counselling and that absent bleeding may be viewed as a positiv e outcome.