Martins W P, Nastri C O, Rienzi L, van der Poel S Z, Gracia C, Racowsky C
SEMEAR Fertilidade, Reproductive Medicine, Ribeirão Preto, Brazil.
Department of Obstetrics and Gynecology, Ribeirão Preto Medical School, University of Sao Paulo, Ribeirão Preto, Brazil.
Ultrasound Obstet Gynecol. 2017 May;49(5):583-591. doi: 10.1002/uog.17327. Epub 2017 Apr 10.
Blastocyst transfer in assisted reproduction techniques could be advantageous because the timing of exposure of the embryo to the uterine environment is more analogous to a natural cycle and permits embryo self-selection after activation of the embryonic genome on day 3. Conversely, the in-vitro environment is likely to be inferior to that in vivo, and in-vitro culture beyond embryonic genomic activation could potentially harm the embryo. Our objective was to identify, appraise and summarize the available evidence comparing the effectiveness of blastocyst vs cleavage-stage embryo transfer.
This was a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing the transfer of blastocysts (days 5-6) with the transfer of cleavage-stage embryos (days 2-3) in women undergoing in-vitro fertilization or intracytoplasmic sperm injection. The last electronic searches were run on 1 August 2016. Abstracts and studies with a mean difference between the two study groups of > 0.5 for the number of embryos transferred were excluded.
We screened 1187 records and assessed 33 potentially eligible studies. Twelve studies were included, comprising a total of 1200 women undergoing blastocyst transfer and 1218 undergoing cleavage-stage embryo transfer. We observed low-quality evidence of no significant difference of blastocyst transfer on live birth/ongoing pregnancy (relative risk (RR), 1.11 (95% CI, 0.92-1.35), 10 RCTs, 1940 women, I = 54%), clinical pregnancy (RR, 1.10 (95% CI, 0.93-1.31), 12 RCTs, 2418 women, I = 64%), cumulative pregnancy (RR, 0.89 (95% CI, 0.67-1.16), four RCTs, 524 women, I = 63%) and miscarriage (RR, 1.08 (95% CI, 0.74-1.56), 10 RCTs, 763 pregnancies, I = 0%). There was moderate-quality evidence of a decrease in the number of women with surplus embryos after the blastocyst-stage embryo transfer (RR, 0.78 (95% CI, 0.66-0.91)). Overall, the quality of the evidence was limited by the quality of the included studies and by unexplained inconsistency across studies.
Current evidence shows no superiority of blastocyst compared with cleavage-stage embryo transfer in clinical practice. As the quality of the evidence for the primary outcomes is low, additional well-designed RCTs are still needed before robust conclusions can be drawn. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.
辅助生殖技术中的囊胚移植可能具有优势，因为胚胎暴露于子宫环境的时间更类似于自然周期，并且在第3天胚胎基因组激活后允许胚胎进行自我选择。相反，体外环境可能不如体内环境，并且在胚胎基因组激活后进行体外培养可能会对胚胎造成潜在伤害。我们的目的是识别、评估和总结比较囊胚与卵裂期胚胎移植有效性的现有证据。
这是一项对随机对照试验（RCT）的系统评价和荟萃分析，比较了接受体外受精或卵胞浆内单精子注射的女性中囊胚（第5 - 6天）移植与卵裂期胚胎（第2 - 3天）移植的情况。最后一次电子检索于2016年8月1日进行。排除了两个研究组之间移植胚胎数量的平均差异>0.5的摘要和研究。
我们筛选了1187条记录并评估了33项可能符合条件的研究。纳入了12项研究，共有1200名女性接受囊胚移植，1218名女性接受卵裂期胚胎移植。我们观察到低质量证据表明，囊胚移植在活产/持续妊娠方面无显著差异（相对风险（RR），1.11（95%可信区间，0.92 - 1.35），10项RCT，1940名女性，I² = 54%），临床妊娠方面（RR，1.10（95%可信区间，0.93 - 1.31），12项RCT，2418名女性，I² = 64%），累积妊娠方面（RR，0.89（95%可信区间，0.67 - 1.16），4项RCT，524名女性，I² = 63%）以及流产方面（RR，1.08（95%可信区间，0.74 - 1.56），10项RCT，763例妊娠，I² = 0%）。有中等质量证据表明，囊胚期胚胎移植后有多余胚胎的女性数量减少（RR，0.78（95%可信区间，0.66 - 0.91））。总体而言，证据质量受到纳入研究的质量以及各研究间无法解释的不一致性的限制。
目前的证据表明，在临床实践中，囊胚移植并不优于卵裂期胚胎移植。由于主要结局的证据质量较低，在得出确凿结论之前仍需要更多设计良好的RCT。版权所有©2016国际妇产科超声学会。由约翰·威利父子有限公司出版。
