Correlation between aneuploidy and blastocyst quality

Abstract

To carry out a detailed investigation of the impact of aneuploidy on blastocyst quality. Retrospective Study in an In Vitro Fertilization Laboratory. 1030 cleavage-stage embryos from 156 patients (average maternal age 34.7 years ±5.5) were investigated. Comprehensive chromosome analysis involved the use of microarray comparative genomic hybridisation (aCGH) method on single blastomere biopsied on day 3 of embryo development. Embryo morphology was assessed and recorded on days 3 and/or 5-6 post-fertilisation. Morphologic grade A-C was assigned to the blastocysts with grade A being the highest grade and grade C the lowest. Among 1030 embryos that were analyzed, 389 (37.8%) were euploid and 641 (62.2%) were aneuploid. 261/389 (67.1%) euploid embyos developed to blastocyst while 205/641 (32%) aneuploid embryos grew to blastocysts (p<0.001). At the blastocyst stage the best quality embryos (grade A) were in their majority (144/213 or 67.6%) euploid. Of the 173 average quality blastocyts (grade B) 99 were euploid (57.2%) and 18/80 (22.5%) of poor quality blastocyst (grade C) were euploid. Importantly, among the best quality aneuploidy blastocysts, 42/69 (60.9%) were found to be affected by a single aneuploidy. Blastocyst morphology showed a significant link to aneuploidy (p<0.05), as approximately 67.6% of the best quality embryos were chromosomally normal, and the remaining abnormal. Meanwhile, only 22.5% of poor quality blastocysts were euploid. Most abnormal high quality blastocysts had a single anomaly.