Assessment of day-3 morphology and euploidy for individual chromosomes in embryos that develop to the blastocyst stage.

Objective: To examine the relationship between day-3 morphology and euploidy for individual chromosomes in embryos that develop to the blastocyst stage by day 5.

Design: Retrospective cohort study.

Setting: Boston IVF, a large university-affiliated reproductive medicine practice.

Patient(s): Ninety-nine patients undergoing their first preimplantation genetic screening (PGS) cycle between January 1 and December 31, 2006.

Intervention(s): In vitro fertilization (IVF) and preimplantation genetic screening (PGS).

Main Outcome Measure(s): Prevalence of euploidy for chromosomes X, Y, 8, 13, 14, 15, 16, 17, 18, 20, 21, and 22 in day-3 high implantation potential (HIP) versus non-HIP embryos that grew to day-5 blastocysts.

Result(s): Seven hundred three embryos from 99 cycles in 99 patients underwent PGS. Three hundred sixty-four (52%) embryos from 88 cycles in 88 patients developed to the blastocyst stage by day 5. High implantation potential embryos were more likely to be euploid for chromosomes X/Y, 8, 15, 16, 18, and 22 compared with non-HIP embryos, with similar trends for chromosomes 14 and 17. There were no statistically significant differences between HIP and non-HIP embryos in euploidy prevalence for chromosomes 13, 20, and 21.

Conclusion(s): Our data suggest that PGS may detect potentially viable but detrimental chromosomal abnormalities that are not detected by embryo morphology alone.