Background and Significance: Preimplantation genetic diagnosis (PGD) may be useful in screening for chromosomal abnormalities in patients undergoing MESA and TESE procedures. It has been reported that there is a correlation between embryonic morphology and chromosomal defects. It is currently unknown if this correlation exists in cycles with MESA/TESA, and ICSI.

Objective: To evaluate the incidence of chromosome abnormalities in embryos derived from MESA/TESE and ICSI and its relationship to embryo stages and grading.

Materials and Methods: Patients with severe male factors requiring MESA/TESE and ICSI who also had PGD performed were included in this study. Patients who had PGD with ejaculated sperm (EJAC) served as control. PGD was performed by FISH with probes for chromosomes 13, 18, 21, X, and Y. Additional chromosome 8, 9, 14, 15, 16, 17, 20, and 22 were examined if indicated. Each embryo was staged and graded. Statistical analyses were performed using χ2 and Fisher tests.

Results: The overall rates for euploidy decreased in embryos with poorer grading scores (Fig. 1). This trend was similar among MESA, TESE, and EJAC groups. In MESA/TESE groups, embryos with Grade A/B were 51.7% chromosomally normal as compared to 19.2% with Grade C/D (p=.034), and this was not statistically different from the EJAC group (Fig. 2). Embryos that were 7–8 cells at biopsy had the highest rate of euploidy as compared to embryos >8 cells or <7 cells (p<.05; Fig. 3), with no difference in this finding between the MESA/TESE and EJAC groups. There was no difference in the rate of euploidy between embryos with even and odd blastomere numbers.

Conclusion: Chromosomally normal embryos from MESA and TESE patients, similar to EJAC group, are associated with embryos of higher grades. Embryos with grade A have normal chromosomes at least three times of embryos with grade D (64.7%:20.0%). Embryos at 7 and 8 cell stages at the time of PGD have the highest incidence of normal chromosomes in both MESA/TESA and naturally ejaculated patients. Our study shows that chromosome patterns in embryos derived from MESA/TESA correlate with the embryonic stages and development.

Figure 1. Relationship between chromosome abnormality and embryo grading.

Figure 2. Normal chromosome rates by embryo grade.

Figure 3. Relationship between chromosomal abnormality and blastomere number.

Site Index