Objective       To investigate the best time for placing the levonorgestrel releasing intrauterine system (brand name: Mirena) in the treatment of adenomyosis in order to achieve the therapeutic efficacy and reduce side effects at the same time.       Methods      Clinical data of 1 372 women taking Mirena treatment for adenomyosis in our department from the years of 2002 to 2014 were collected and retrospectively analyzed in this study. According to the time for placing Mirena

they were divided into 3 groups

that is

group A (placed in 3-7 d after menstruation

n=110)

group B (in the 3rd-5th days during menstruation

n=1 198) and group C (immediately after abortion/curettage

n=64). Pain relief

menstrual changes

vaginal spotting and amenorrhea were studied to evaluate the efficacy of Mirena.       Results      There were no significant differences in pain relief and amenorrhea occurrence among the 3 groups after Mirena placement (P0.05). The patients of group C had an obvious trend in decreased volume of menstrual flow when compared with those of group A and group B (P0.05). The incidence of intermenstrual vaginal bit bleeding were significant different among the 3 groups (P0.05)

and the patients of groups A and group B had remarkably longer vaginal spotting (P0.05).       Conclusion      Placing Mirena in different periods of menstrual cycle can alleviate the dysmenorrhea caused by adenomyosis. And the placement immediately after abortion/curettage can reduce the hormone relative adverse reactions

and achieve better efficiency.