OBJECTIVE To determine if transferring a lower-quality embryo with a good-quality blastocyst is detrimental, given that evidence suggests that embryos can signal the endometrium and that embryo quality may affect negatively endometrial receptivity. DESIGN Retrospective cohort study. SETTING In vitro fertilization center. INTERVENTION(S) Single- versus double-embryo transfer. PATIENT(S) Patients with a double-embryo transfer of a good-quality blastocyst plus a lower-quality blastocyst, early blastocyst, or morula were compared with patients receiving a single good-quality blastocyst. MAIN OUTCOME MEASURE(S) Live birth, multiple gestation. RESULT(S) In this study, 4,640 in vitro fertilization cycles were analyzed. In none of the analyses did transferring a second lower-quality embryo negatively affect birth rate. In the primary analysis, transferring a second lower-quality embryo increased live birth by 10% and the multiple birth rate by 15%. The addition of a fair- or poor-quality blastocyst or early blastocyst markedly increased the twin birth rate by 22%-27% with an 8%-12% increase in live birth. The addition of a morula did not increase live birth but resulted in 12% more multiples. In women younger than 38 years, adding a lower-quality embryo increased the birth rate by 7% but resulted in 18% increase in multiples. In women 38 years or older, adding a lower-quality embryo increased the live birth rate by 9% with a 15% increase in multiples. CONCLUSION(S) Addition of a lower-quality embryo does not have a detrimental effect on a good-quality blastocyst and results in a small increase in live births. However, this is at the expense of a marked increase in the likelihood of multiple gestations.

中文翻译：

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转移具有优质囊胚的低质量胚胎是否会损害活产的可能性？

目的 确定移植具有优质囊胚的低质量胚胎是否有害，因为有证据表明胚胎可以向子宫内膜发出信号，并且胚胎质量可能会对子宫内膜容受性产生负面影响。设计 回顾性队列研究。设置 体外受精中心。干预措施 单胚胎移植与双胚胎移植。患者 将优质囊胚加低质量囊胚、早期囊胚或桑椹胚双胚移植的患者与接受单个优质囊胚的患者进行比较。主要结果测量活产，多胎妊娠。结果 在这项研究中，分析了 4,640 个体外受精周期。在所有分析中，移植第二个低质量胚胎都没有对出生率产生负面影响。在初步分析中，移植第二个较低质量的胚胎使活产率增加了 10%，多胞胎率增加了 15%。添加质量一般或较差的囊胚或早期囊胚可显着增加双胞胎出生率 22%-27%，活产率增加 8%-12%。添加桑椹树并没有增加活产率，但会增加 12% 的倍数。在 38 岁以下的女性中，添加质量较低的胚胎可将出生率提高 7%，但会导致倍数增加 18%。在 38 岁或以上的女性中，添加较低质量的胚胎可使活产率提高 9%，倍数增加 15%。结论(S) 添加低质量胚胎不会对高质量囊胚产生不利影响，并会导致活产婴儿略有增加。然而，