Whitney John B, Balloch Katie, Anderson Robert E, Nugent Nancy, Schiewe Mitchel C
Ovation Fertility, ART Lab, Newport Beach, CA 92663 USA.
Southern California Center for Reproductive Medicine, Newport Beach, CA 92663 USA.
JBRA Assist Reprod. 2019 Jan 31;23(1):45-50. doi: 10.5935/1518-0557.20180089.
To determine if Day 7 blastocysts merit biopsy, vitrification and transfer consideration by contrasting their aneuploidy and implantation rates to Day 5 and 6 blastocysts.
A total of 1,925 blastocysts were biopsied from 402 PGT-A cycles over a 12 to 16 month interval. All embryos were cultured under tri-gas, humidified conditions (37ºC) for up to 7 days (168 hours post-insemination). Biopsied blastocysts were vitrified and trophectoderm samples analyzed using NextGen sequencing. Single euploid embryo transfers were performed (n=254) using either a Day 5 (n=145), Day 6 (n=92) or a Day 7 blastocyst (n=16) post-warming. Euploidy rates and pregnancy outcomes were subsequently assessed and differences determined by day of development and blastocyst quality grade.
No differences were observed in implantation, pregnancy loss or ongoing pregnancy rates between Day 5 and Day 6 blastocysts. Development to Day 7 accounted for 6.6% of all blastocysts. Euploidy rates were higher in Day 5 blastocysts (53.5%; <0.05) compared to Day 6 (40.4%) and Day 7 (35.9%). High implantation potential (56.3% to 79.3%) of vitrified-warmed euploid blastocyst occurred independent to the day of development. However, miscarriage/loss rates increased (22.2% vs. 2%; <0.05) with Day 7 blastocysts, resulting in lower (<0.05) live birth rates (43.8% vs. 67.4-77.2%).
Culturing blastocysts to Day 7 has proven beneficial by achieving viable euploid embryos that would have otherwise been discarded. An extra Day of embryo growth allows select patients additional opportunities for in vitro development and possible healthy term live births.
通过对比第7天囊胚与第5天和第6天囊胚的非整倍体率和着床率，确定第7天囊胚是否值得进行活检、玻璃化冷冻及移植考虑。
在12至16个月的时间间隔内，从402个植入前基因诊断非整倍体检测（PGT-A）周期中获取了总共1925个囊胚进行活检。所有胚胎均在三气、加湿条件（37℃）下培养长达7天（授精后168小时）。对活检后的囊胚进行玻璃化冷冻，并使用新一代测序技术分析滋养外胚层样本。解冻后，使用第5天（n = 145）、第6天（n = 92）或第7天囊胚（n = 16）进行单倍体胚胎移植（n = 254）。随后评估整倍体率和妊娠结局，并根据发育天数和囊胚质量等级确定差异。
第5天和第6天囊胚在着床、妊娠丢失或持续妊娠率方面未观察到差异。发育至第7天的囊胚占所有囊胚的6.6%。与第6天（40.4%）和第7天（35.9%）相比，第5天囊胚的整倍体率更高（53.5%；P<0.05）。玻璃化冷冻解冻后的整倍体囊胚具有较高的着床潜力（56.3%至79.3%），且与发育天数无关。然而，第7天囊胚的流产/丢失率增加（22.2%对2%；P<0.05），导致活产率降低（P<0.05）（43.8%对67.4 - 77.2%）。
将囊胚培养至第7天已被证明是有益的，可获得原本会被丢弃的有活力的整倍体胚胎。额外一天的胚胎生长为特定患者提供了更多体外发育机会以及实现健康足月活产的可能。
