Randomised comparative trial of the levonorgestrel intrauterine system and mefenamic acid for the treatment of idiopathic menorrhagia: a multiple analysis using total menstrual fluid loss, menstrual blood loss and pictorial blood loss assessment charts.

OBJECTIVE: To compare the efficacy and tolerability of the levonorgestrel intrauterine system (LNG IUS) with mefenamic acid in the management of objective idiopathic menorrhagia.

DESIGN: Phase III, Single centre, open, randomised, comparative, parallel group study.

SETTING: District General Hospital in the United Kingdom.

POPULATION: Fifty-one women with objective menorrhagia.

METHODS: Twenty-five women randomised to receive the LNG IUS and 26 to oral mefenamic acid for six cycles.

MAIN OUTCOME MEASURES: Change from baseline in menstrual blood loss (MBL), total menstrual fluid loss (TMFL) and pictorial blood loss assessment chart (PBAC) score at the third and sixth cycle of treatment.

RESULTS: After six cycles the median menstrual blood loss was 5 mL in the LNG IUS group and 100 mL in the mefenamic acid group (P < 0.001). Median TMFL was 27 mL in the LNG IUS group and 157 mL in the mefenamic acid group (P < 0.001). Median PBAC score was 25 in the LNG IUS group and 159 in the mefenamic acid group. Changes in menstrual blood loss correlated strongly to changes in TMFL (r= 0.88) but PBAC correlated less well to blood loss and total fluid loss (r= 0.53 and r= 0.58).

CONCLUSIONS: Both the LNG IUS and mefenamic acid significantly decreased menstrual blood loss, TMFL and PBAC scores. The LNG IUS produced greater reductions in all parameters than mefenamic acid. Comparison of the different measurements suggests that TMFL assessment may be an easier and a more relevant measure of symptom severity than menstrual blood loss.