Letrozole versus clomiphene citrate in polycystic ovary syndrome: systematic review and meta-analysis

Abstract

The objective of the present systematic review and meta-analysis was to examine the literature and to identify the results of randomized controlled trials (RCTs) comparing the use of letrozole to clomiphene citrate (CC) for ovulation induction in patients with polycystic ovary syndrome (PCOS). An exhaustive electronic literature search was performed using the MEDLINE and EMBASE databases until October 2014. Seven prospective RCTs comparing the use of letrozole to CC in PCOS patients met the inclusion criteria. Overall, the seven included studies accounted for 1833 patients (906 in the letrozole group and 927 in the CC group) and for 4999 ovulation induction cycles (2455 in the letrozole group and 2544 in the CC group). Five of the included studies reported data on live birth rates. There was a statistically significant increase in the live birth and pregnancy rates in the letrozole group when compared to the CC group, with a relative risk (RR) = 1.55 (95% confidence interval (CI): 1.26–1.90; I²= 0%) and RR = 1.38 (95% CI: 1.05–1.83; I²= 61%), respectively. There were no differences in the multiple pregnancy, miscarriage and ovulation rates between the two groups. Our study found that letrozole is superior to CC when considering the live birth and pregnancy rates in patients with PCOS.

Chinese abstract

这个系统性回顾和meta分析的目的是检测文献和确定随机对照试验的结果（RCTs），比较来曲唑和克罗米芬（CC）诱导多囊卵巢综合征(PCOS)患者的排卵。广泛收集2014年10月以前MEDLINE和EMBASE数据库的电子文献。发现7个符合标准的比较在PCOS患者中应用来曲唑和CC的诱导排卵的前瞻性RCTs研究。7个纳入的研究共1833个患者(来曲唑组906 、CC组927)和4999个诱导排卵周期（来曲唑组2455，CC组 2544）。纳入的研究有5项报告了活产率。来曲唑组活产率和妊娠率明显高于CC组，分别为RR=1.55(95% CI：1.26–1.90; I2 = 0%)，RR = 1.38 (95% CI: 1.05–1.83; I2=61%)。多胎妊娠率、流产率、排卵率在两组间没有明显差异。研究发现PCOS患者应用来曲唑活产率和妊娠率优于CC。

Keywords:

• Clomiphene citrate
• letrozole
• PCOS

Acknowledgements

English-language editing of this manuscript was provided by Journal Prep.

Declaration of interests

The authors report no conflicts of interest.

Supplementary material available online.