Does the prevalence of individual chromosomal aneuploidy vary with respect to day 3 embryo morphology?

Abstract

Preimplantation genetic diagnosis (PGD) has been increasingly utilized in conjunction with embryo morphology grading to select embryos for transfer. Our group previously reported that High Implantation Potential (HIP) embryos are more likely to develop to the blastocyst stage, but a significant proportion of those are aneuploid. We aim to compare proportions of aneuploidy among individual chromosomes in HIP and non-HIP embryos that develop to the blastocyst stage by day 5. Retrospective analysis. We identified all women who underwent in vitro fertilization (IVF) with their first PGD cycle for recurrent miscarriage, recurrent IVF failure, advanced maternal age, or other indications between January 1 and December 31, 2006. Embryos were scored as HIP if they had ≥4 cells on day 2 and ≥7 cells on day 3, with <20% fragmentation and no multinucleation. Fluorescence in situ hybridization was utilized to analyze 9 or 12 chromosomes. P values were adjusted to account for lack of independence among embryos from the same woman. A total of 364 embryos from 88 cycles in 88 patients were analyzed. Non-HIP embryos were more likely to be aneuploid for chromosomes XY, 8, 15, 16, 18, and 22 compared to HIP embryos, with similar trends for chromosome 14 and 17. There were no significant differences between HIP and Non-HIP embryos in the aneuploidy rates of chromosomes 13, 20, and 21. TableAneuploidy Prevalence by ChromosomeChromosomeHIPNon-HIPPXY18/205 (9%)25/148 (17%)0.04811/63 (17%)12/34 (35%)0.011343/204 (21%)36/149 (24%)0.491417/68 (25%)15/35 (43%)0.091538/198 (19%)48/143 (34%)0.0011637/200 (19%)40/149 (27%)0.0471720/200 (10%)26/149 (17%)0.051838/204 (19%)45/149 (30%)0.012016/63 (25%)9/34 (26%)0.902146/206 (22%)34/150 (23%)0.942236/199 (18%)39/147 (27%)0.02No Nucleus4/210 (2%)4/154 (3%)0.64 Open table in a new tab Aneuploidy is common in embryos that develop to the blastocyst stage. Non-HIP embryos are associated with increased aneuploidy for most screened chromosomes, suggesting an association between morphology and chromosomal status. Interestingly, HIP embryos are no less likely to have abnormal numbers of chromosomes 13, 20, and 21. Our data suggest that PGD is a useful tool to detect embryos with potentially viable but detrimental chromosomal abnormalities that are not detected by embryo morphology alone.