Yang Zhihong, Salem Shala A, Liu Xiaohong, Kuang Yanping, Salem Rifaat D, Liu Jiaen
ART and PGD Program, Pacific Reproductive Center, Torrance, CA, USA.
Mol Cytogenet. 2013 Aug 9;6(1):32. doi: 10.1186/1755-8166-6-32.
In assisted reproductive treatments, embryos remaining after fresh embryo transfer are usually selected for cryopreservation based on traditional morphology assessment. Our previous report has demonstrated that array comparative genomic hybridization (aCGH) screening for IVF patients with good prognosis significantly improves clinical and ongoing pregnancy rates in fresh embryo transfer cycles. The current study further investigates the efficiency of applying aCGH in the selection of euploid embryos for cryopreservation as related to pregnancy and implantation outcomes in subsequent frozen embryo transfer (FET) cycles.
First-time IVF patients with good prognosis undergoing fresh single embryo transfer and having at least one remaining blastocyst for cryopreservation were prospectively randomized into two groups: 1) Group A patients had embryos assessed by morphology first and then by aCGH screening of trophectoderm cells and 2) Group B patients had embryos evaluated by morphology alone. All patients had at least one blastocyst available for cryopreservation after fresh embryo transfer. There were 15 patients in Group A and 23 patients in Group B who failed to conceive after fresh embryo transfer and completed the FET cycles. Blastocyst survival and implantation rates were compared between the two groups.
There were no significant differences in blastocyst survival rates between Group A and Group B (90.9% vs. 91.3%, respectively; p >0.05). However, a significantly higher implantation rate was observed in the morphology assessment plus aCGH screening group compared to the morphology assessment alone group (65.0% vs. 33.3%, respectively; p = 0.038). There was no miscarriage observed in Group A while a 16.7% miscarriage rate was recorded in Group B (0% vs. 16.7%, respectively; p >0.05).
While aCGH screening has been recently applied to select euploid blastocysts for fresh transfer in young, low-risk IVF patients, this is the first prospective study on the impact of aCGH specifically on blastocyst survival and implantation outcomes in the subsequent FET cycles of IVF patients with good prognosis. The present study demonstrates that aCGH screening of blastocysts prior to cryopreservation significantly improves implantation rates and may reduce the risk of miscarriage in subsequent FET cycles. Further randomized clinical studies with a larger sample size are needed to validate these preliminary findings.
在辅助生殖治疗中，新鲜胚胎移植后剩余的胚胎通常根据传统形态学评估来选择进行冷冻保存。我们之前的报告表明，对预后良好的体外受精（IVF）患者进行微阵列比较基因组杂交（aCGH）筛查可显著提高新鲜胚胎移植周期的临床妊娠率和持续妊娠率。本研究进一步探讨了应用aCGH筛选整倍体胚胎用于冷冻保存与后续冷冻胚胎移植（FET）周期的妊娠及着床结局之间的关系。
将首次接受IVF治疗、预后良好、进行新鲜单胚胎移植且至少有一个剩余囊胚可供冷冻保存的患者前瞻性随机分为两组：1）A组患者先通过形态学评估胚胎，然后对滋养外胚层细胞进行aCGH筛查；2）B组患者仅通过形态学评估胚胎。所有患者在新鲜胚胎移植后至少有一个囊胚可供冷冻保存。A组有15例患者，B组有23例患者在新鲜胚胎移植后未受孕并完成了FET周期。比较两组的囊胚存活率和着床率。
A组和B组的囊胚存活率无显著差异（分别为90.9%和91.3%；p>0.05）。然而，与仅进行形态学评估的组相比，形态学评估加aCGH筛查组的着床率显著更高（分别为65.0%和33.3%；p = 0.038）。A组未观察到流产，而B组记录到16.7%的流产率（分别为0%和16.7%；p>0.05）。
虽然最近已应用aCGH筛选整倍体囊胚用于年轻、低风险IVF患者的新鲜移植，但这是第一项专门研究aCGH对预后良好的IVF患者后续FET周期中囊胚存活和着床结局影响的前瞻性研究。本研究表明冷冻保存前对囊胚进行aCGH筛查可显著提高着床率，并可能降低后续FET周期的流产风险。需要进一步开展更大样本量的随机临床研究来验证这些初步发现。
