2. Randomization and masking
Patients were allocated (1:1:1) to
one of three treatment arms: MA alone (control group), LNG-IUS alone, or
MA+LNG-IUS group by the simple randomization. Randomization sequences
were prepared according to random-number tables. The treatment
allocation was concealed before the participants were successfully
enrolled. This study was open-labelled that all patients and study
physicians were aware of the treatment assignment. None of the
clinicians who performed the hysteroscopic evaluation on patients in
this trial and none of the pathologists who assessed the specimens from
this trial was aware of the treatment allocations.