中文摘要：

目的：系统评价不同剂量的来曲唑（LE）对多囊卵巢综合征（PCOS）患者的疗效，为临床用药提供一定的依据。方法：计算机检索中国知网、维普、万方、Pubmed、TheCochraneLibrary、ScienceDirect等数据库，提取出相关的随机对照试验，对各文献进行质量评价后，采用RevMan5．3软件分析患者的促排卵结局和妊娠结局。结果：①共有9篇文献纳入本研究中，包含816例PCOS患者，共计816个周期；②Meta分析显示2．5mgLE与5．0mgLE在排卵率、流产率、不良事件（多胎妊娠和卵巢过度刺激综合征1发生率及hCG注射日子宫内膜厚度之间的差异均无统计学意义（P〉0．05），而5．0mg组的妊娠率高于2．5mg组，差异具有统计学意义（RR=0．58，P=0．001）；5．0mg组与7．5mg组在排卵率、周期妊娠率、不良事件发生率、hCG注射日子宫内膜厚度之间的差异均无统计学意义（P〉0．05）。结论：在临床上对有生育要求的PCOS患者可使用LE促排卵时，5．0mg剂量有着更高的妊娠率，值得在临床上推广使用。对于效果不佳者，进一步提高剂量并未显示有提高疗效的作用。

英文摘要：

Objective： To evaluate the effectiveness and safety of three different dosage of letrozole （LE） for ovulation induction in patients with polycystic ovary syndrome （PCOS）. Methods： Pubmed, Cochrane Library, ScienceDirect, CNKI, Wanfang, VIP were searched for relevant randomized controlled trials （RCTs）. Two reviewers selected trials and assessed trial quality independently. Meta-analysis was performed by Revman 5.3 software with the fix-effects model or random-effects model according to the heterogeneity. Results： Nine relevant RCTs studies involving 816 women and 816 cycles were included. There were no significant differences in the ovulation rate, the miscarriage rate, adverse event incidence, and endometrial thickness on the day of hCG administration between 2.5 mg group and 5.0 mg group. But the pregnancy rate per cycle was significant higher in 5.0 mg group than in 2.5 mg group. There were no significant differences in the ovulation rate, the pregnancy rate per cylce, adverse event incidence, and the endometrial thickness on the day ofhCG administration between 5.0 mg group and 7.5 mg group. Conclusion： It appears that 5.0 mg LE is a preferable dosage for ovulation induction in infertile women with PCOS because of its high pregnancy rate.