Pre-treatment with Mifepristone before Mirena insertion helps optimize the bleeding pattern

Pretreatment with low dose Mifepristone significantly improves the bleeding pattern following the insertion of the levonorgestrel-releasing intrauterine system with a 52 mg reservoir (LNG-IUS 52 mg, Mirena®) report the results of randomized control trial published in Journal of Human Reproduction.

The LNG-IUS is one of the most cost-effective contraceptive method currently available, but many women discontinue its use because of irregular bleeding/spotting during the initial three months following its placement. It is estimated that about 25–62% of women experience irregular vaginal bleeding during the first 3-6 months causing them to discontinue the contraceptive.

With continued use after 3-6 months, the irregular bleeding and spotting are reduced, and more than half the women experience amenorrhea at the end of 1 year.

The Swedish researchers recruited 68 eligible women attending the Karolinska University Hospital from November 2009-2013 for this prospective, randomized, double-blind, placebo-controlled trial (European Union Clinical Trials Register–2009-009014-40). Fifty-eight women met the eligibility criteria and were randomized to receive 50 mg mifepristone as single oral dose or placebo for two months before and three days following the insertion of LNG-IUS.

The LNG-IUS insertion was timed at the end of two 28 days menstrual cycle. All women were asked to systemically note the daily bleeding and spotting (B/S) or adverse effects for two months of mifepristone treatment and six months following the insertion of LNG-IUS.

The study participants underwent routine physical and gynecological examination, required laboratory tests including pelvic ultrasound, tests for chlamydia infection, breast biopsy, endometrial biopsy and pap test at baseline and during follow-up.

After statistical analysis, researchers noted significant lower B/S in the mifepristone group (−17.8% points, P < 0.001) in the first month following the LNG-IUS insertion. However, no significant difference was observed in both groups in the subsequent months.

This European study is the first study investigating the effect of prophylactic use of progesterone receptor modulators to reduce the B/S associated with post-LNG-IUS insertion. Other studies have investigated mifepristone for therapeutic purposes.

Based on the study results, researchers are optimistic that other modified treatment protocols of mifepristone with different duration and dose could be explored in further studies. Studies could also be planned with other progesterone receptor modulators to address the issue of B/S immediately after LNG-IUS insertion.

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