释放左旋18甲基炔诺酮的宫内节育器(LNG-IUD)广泛用于临床已五年多,其妊娠率极低;与放置前相比经血量显著降低,出血及点滴出血天数减少,痛经症状减轻,而且没有盆腔炎的发生。其中经血量明显减少是最显著的特点,组织学研究证实系由于 LNG 对子宫内膜的局部作用,经子宫 Intrauterine devices (LNG-IUDs) that release levonorgestrel 18 are widely used in the clinic for more than five years and have a very low pregnancy rate; blood loss is significantly reduced compared to before placement, and the number of bleeding and spotting days is reduced , Dysmenorrhea symptoms, and no occurrence of pelvic inflammatory disease. Which significantly reduced the amount of blood is the most significant feature of histological studies confirm that due to the local role of LNG on the endometrium, the uterus