A Cochrane review included 3 RCTs. There was a reduction in the recurrence of painful periods in the LNG-IUS group compared with expectant management (RR 0.22, 95% CI 0.08 to 0.60; 2 trials, n=95). The proportion of women who were satisfied with their treatment was higher in the LNG-IUD group than in the control group (RR 1.21, 95% CI 0.80 to 1.82, n=95). The number of women reporting a change in menstruation was significantly higher in the LNG-IUD group (RR 37.80, 95% CI 5.40 to 264.60, n=95) but the number of women not completing the allocated treatment did not differ between groups (RR 0.66, 95% CI 0.08 to 5.25). Women receiving LNG-IUD noted lower pain scores compared with women receiving gonadotrophin-releasing hormone agonists (MD -0.16, 95% CI -2.02 to 1.70; 1 trial, n=40) but this did not reach statistical significance.
Comment: The quality of evidence is downgraded by study quality (unclear blinding of participants and personnel).