目的：分析高龄女性患者（40岁≤年龄≤50岁）进行冻融胚胎移植时移植单个卵裂期胚胎、双卵裂期胚胎以及单个囊胚移植的妊娠结局及活产率相关因素。方法：选取2010年1月至2018年6月间的高龄患者,按照患者移植胚胎数量以及阶段将患者分为3组,其中移植冷冻单个卵裂胚患者[移植受精第3天的胚胎（D3组）,n=1 363],移植冷冻双卵裂期胚胎患者[移植2枚第3天的胚胎（2D3组）,n=5 248],移植冷冻单个囊胚患者{移植第5天或者第6天的胚胎[囊胚移植（blastocyst transfer, BT）组],n=495},比较3组间的活产结局以及相关指标,采用多因素Logistic回归法进一步分析高龄患者活产率相关因素。结果：3组（D3组、2D3组、BT组）间两两比较,活产率（6.53%比13.38%比18.38%）差异均有统计学意义（P均<0.001）,其中2D3这一组的双胎活产率最高（1.12%比7.98%比1.10%）,3组间两两比较,双胎活产率差异有统计学意义（P均<0.05）。经多因素Logistic回归分析,以2D3组的活产率作为参照,D3组的活产率较低（OR=0.558,95%CI为0.440~0.707,P<0.001）;BT组的活产率则有略高趋势,但差异尚无统计学意义（OR=1.257,95%CI为0.977~1.617,P=0.075）。患者年龄越大（OR=0.685, 95%CI为0.654~0.718）、体质量指数越高（OR=0.961, 95%CI为0.935~0.987）、内膜准备方案采用激素替代周期（以促排卵周期为参考,OR=0.736, 95%CI为0.631~0.857）,则活产率越低;而内膜厚度越厚（OR=1.058, 95%CI为1.024~1.094）,则活产率越高（P<0.05）。同时对处于40、41、42、43、44、45岁的患者依次进行各年龄的活产率统计,发现在不同年龄BT组均有着更高的活产率（P=0.024、0.010、0.198、0.009、0.102、0.064）（44岁、45岁除外）,且随着年龄增长,活产率逐渐降低。结论：高龄患者行单个囊胚移植可以达到与双卵裂期胚胎移植相似的活产率,但其双胎率更低。

Objective: To analyze the pregnancy outcome and influencing factors related to live birth rate of single cleavage-stage embryos, double cleavage-stage embryos and single blastocyst transfer in elderly patients (40≤age≤50 years) who underwent frozen-thawed embryo transfer. Methods: The elderly patients undergone frozen-thawed embryo transfer from January 2010 to June 2018 were enrolled. The patients were divided into three groups according to the number and stage of transferred embryo: Group D3(Day3, embryo transferred was the third day after fertilization, n=1 363), Group 2D3(two embryos transferred were the third day after fertilization, n=5 248) and Group BT (blastocyst transferred was the fifth or sixth day after fertilization, n=495). Live birth outcome was analyzed and related influencing factors were explored by multivariate Logistic regression. Results: There were significant differences in live birth rates (6.53% vs. 13.38% vs. 18.38%) between the three groups（D3, 2D3, BT）(P<0.01). Twin live birth rate was the highest in 2D3 group (1.12% vs. 7.98% vs. 1.10%)(P<0.05). Multivariate logistic regression analysis revealed that when 2D3 was taken as the reference group, the live birth rate of D3 group was lower (OR=0.558, 95%CI 0.440-0.707, P<0.001), and the live birth rate of BT group had a trend of rising (OR=1.257, 95%CI 0.977-1.617, P=0.075). The live birth rate was negatively correlated with the increase of age（OR=0.685, 95%CI=0.654-0.718） and BMI (OR=0.961, 95%CI=0.935-0.987), and the use of endometrium preparation method (hormone replacement method, with ovulation cycle as reference) might lead to a lower live birth rate(OR=0.736, 95%CI=0.631-0.857). And the live birth rate was positively correlated with thicker endometrium (OR=1.058, 95%CI=1.024-1.094). The live birth rates of patients at 40, 41, 42, 43, 44 and 45 years old were calculated. It was found that the live birth rate was higher in BT group of different ages (P=0.024, 0.01, 0.198, 0.009, 0.102, 0.064), and the live birth rate gradually decreased with the increase of age. Conclusions: Single blastocyst transfer in elderly patients can achieve a similar live birth rate compared to double cleavage-stage embryo transfer, but twin delivery is lower.