新鲜胚胎与冷冻胚胎移植在体外受精周期中疗效比较的Meta分析

背景：胚胎移植的方式主要包括新鲜胚胎移植和冷冻胚胎移植，但两种方法各有优缺点，哪种方法更有利于患者的受孕目前仍存在较大争议。目的：系统评价新鲜胚胎移植与冷冻胚胎移植在体外受精-胚胎移植（IVF）周期中的临床疗效。方法：计算机检索Medline、Cochrane Library、Ovid、EMBASE、中国生物医学、中国期刊全文和万方数据库，以及手工检索国内相关妇产科杂志。检索新鲜胚胎移植与冷冻胚胎移植在IVF周期中的疗效对比的随机对照研究文献，评价指标包括临床妊娠率、持续妊娠率、流产率等。由2名评价者按照纳入与排除标准选择试验，提取资料和评价质量，并采用RevMan 5.2软件进行Meta分析。结果与结论：共纳入随机对照研究3篇，包括633例患者。Meta分析结果显示：冷冻胚胎组在持续妊娠率方面，优于于新鲜胚胎组[OR=0.60，95%CI（0.44，0.84），P=0.003]；在临床妊娠率方面，冷冻胚胎组优于新鲜胚胎组[OR=0.60，95%CI（0.44，0.83），P=0.002]；在流产率方面，2组比较差异无显著性意义[OR=1.23，95%CI（0.60，2.49），P=0.57]。提示在IVF周期中，冷冻胚胎移植在持续妊娠率及临床妊娠率方面优于新鲜胚胎移植。但受纳入研究样本量及方法学质量限制，尚需开展更多大样本、高质量随机对照试验来增加证据的论证强度。

A meta-analysis of clinical efficacy of fresh embryo transfer versus frozen embryo transfer in in vitro fertilization cycles

BACKGROUND： The main methods of embryo transfer include fresh embryo transfer and frozen embryo transfer but these two approaches have their own advantages and disadvantages. Which method is more conducive to the patient＇s conception is still of considerable controversy. OBJECTIVE： To systematically evaluate the clinical efficacy of fresh embryo transfer and frozen embryo transfer in the in vitro fertilization cycles. METHODS： The computer retrieval of Medline, Cochrane Library, Ovid, EMbase, CBM, Wanfang databases and the manual retrieval of relevant journals of gynaecology and obstetrics in China were performed. Literatures concerning randomized controlled trials in relation to the comparison of the clinical efficacy between fresh embryo transfer and frozen embryo transfer in the in vitro fertilization cycles were searched. Moreover, there were two researchers responsible for the independent extraction of data and for the evaluation of methodological quality. Evaluation indexes included clinical pregnancy rate, on-going pregnancy rate and miscarriage rate. Then the meta-analysis was conducted by using RevMan 5.2 software. RESULTS AND CONCLUSION： A total of three randomized controlled trials were included, involving 633 patients. The results of the meta-analysis were shown as follows： Compared with the fresh embryo transfer, the frozen embryo transfer was superior in the on-going pregnancy rate and clinical pregnancy rate （odds ratio （OR）=0.60, 95% confidence interval （CI） （0.44,0.84）, P=0.003; OR=0.60, 95%Cl（0.44,0.83）, P=0.002）. However, there was no statistical differences in the miscarriage rate （OR=1.23, 95%Cl（0.60,2.49）, P=0.57）. These findings indicate that the frozen embryo transfer is better than the fresh embryo transfer in clinical pregnancy rate and on-going pregnancy rate. However, the result is limited by the quantity of research samples and methodological quality, and the intensity of its argumentation should be improved through further development of additional large samples, rigorously designed and high-quality randomized controlled trials.