Objective: To evaluate the efficacy, bleeding profile and safety of low-dose levonorgestrel-releasing intrauterine system (LNG-IUS 8) in Chinese healthy women of childbearing age. Methods: A multi-center, open-label, single-arm clinical trial conducted at 16 centres in China enrolled 773 healthy women of childbearing age (mean age 31.6 years old, range 18 to 40 years old) , who demanded contraception, from April 2006 to June 2013. All women placed LNG-IUS 8 for 3 years and then been followed up at 3, 6, 9, 12, 18, 24, 30, 36 months. The efficacy variables including pregnancy rate and expulsion rate were analyzed using life table, while observing adverse events (AE) to evaluate the safety. The bleeding profile happened during the study was assessed using 90-day reference intervals (World Health Organization criteria) . Results: Eight pregnancies occurred among 773 women, resulting in a overall Pearl index of 0.42 per 100 women years. The 3-year cumulative pregnancy rate was 0.37 per 100 women years and the 3-year cumulative expulsion rate was 1.99 per 100 women years. The number of women with bleeding/spotting reduced and the bleeding/spotting days declined over time. Totally 219 AE were reported related to LNG-IUS 8 placements. The most common AE were vaginal bleeding (8.2%, 63/773) and the ovarian cyst (6.2%, 52/773) . LNG-IUS 8 had an improving effect on dysmenorrhea that the percentage of women with dysmenorrhea as well as the days of dysmenorrhea decreased over time. The percentage of women satisfied or very satisfied with LNG-IUS 8 was 87.2% (622/713) . Conclusion: LNG-IUS 8 is highly effective and safe for Chinese healthy women of childbearing age.
目的： 评估低剂量左炔诺孕酮宫内缓释系统（LNG-IUS 8）用于中国健康女性的避孕效果和安全性。 方法： 本研究为多中心、开放、单臂临床试验，2009年4月至2013年6月中国16个临床中心共纳入773例18~40岁要求避孕的健康妇女，放置LNG-IUS 8共3年，分别于第3、6、9、12、18、24、30、36个月进行随访。采用生命表法统计LNG-IUS 8避孕的有效性（妊娠率和脱落率），同时观察使用期间发生的不良事件以评价其安全性。按WHO推荐的90 d为1个参考期评价使用期间的出血模式。 结果： 773例受试者，有8例妊娠，整体比尔指数为0.42/百妇女年，3年累积妊娠率为0.37/百妇女年，3年累积脱落率为1.99/百妇女年。出血/点滴出血的受试者比例呈下降趋势，出血天数与点滴出血天数之和的平均值随时间的延长逐渐减少。有219例（28.3%，219/773）发生了不良事件，最常见为阴道出血（8.2%，63/773）和卵巢囊肿（6.7%，52/773）；随时间推移痛经比例及持续时间均呈下降趋势。87.2%（622/713）的受试者对LNG-IUS 8满意或非常满意。 结论： LNG-IUS 8是1种可供中国健康妇女选择的、安全、有效的避孕方法。.
Keywords: Contraception; Intrauterine devices, medicated; Levonorgestrel; Multicenter study.