Comparison of Preimplantation Genetic Diagnosis-Aneuploidy Screening (PGD-AS) With 5 Chromosome Versus 9/10 Chromosome Panels

Abstract

The purpose of this study was to evaluate the percent of embryos found to be normal using a 5 chromosome panel (PGD5) vs. a 9/10 chromosome panel (PGD9/10) out of total number of embryos biopsied in IVF cycles employing PGD-AS, and the effect of using PGD 5 vs. PGD 9/10 on pregnancy rates. A retrospective analysis of 268 patients undergoing IVF with PGD-AS from September 2003 to May 2004. The medical records were reviewed for age, number of embryos biopsied, number of normal embryos per PGD-AS, number of embryos transferred, and pregnancy outcome including twinning/higher order multiple pregnancies (HOMP) for 4 physicians with similar stimulation protocols. 51 patients met inclusion criteria. Student t-test for two samples and chi-square test were used for statistical analyses. The data for the two groups is shown in Table 1. The mean age, number of total embryos biopsied, and number of embryos transferred were similar between the two groups. The PGD5 group had a higher absolute number and percent of normal embryos diagnosed by PGD (p<0.005, p<0.0001). The pregnancy rate was higher in the PGD5 group, but this did not reach significance. The patients able to conceive (PGD5 or PGD9/10) had a significantly higher number of normal embryos as diagnosed by PGD (4.0 ± 2.2 vs. 2.0 ± 0.97, p<0.0005) and a higher number of embryos transferred (2.5 ± 0.7 vs. 1.9 ± 0.7, p<0.005) as compared to those unable to conceive. One set of quadruplets and two sets of twins were noted in the PGD5 group and one set of quadruplets and three sets of twins in the PGD 9/10 group. Table 1 Tabled 1 A trend towards higher pregnancy rates was noted in the PGD5 group. This may indicate that with an increased number of chromosomes analyzed there is a greater decrease in specificity. A higher number of false-positive abnormal embryos may result in fewer embryos available for transfer. This may lead to transfer of only the remaining available embryos (9/10 chromosome panel) vs. providing a choice to select the best quality embryos for transfer (5 chromosome panel). The comparison of pregnant to non-pregnant women showed a higher number of normal embryos available on day of transfer and a higher number of embryos transferred (perhaps with higher quality as well). The implantation rate was higher in the PGD5 group. This confirms the higher quality of embryos transferred using the 5 chromosome panel vs. the 9/10 chromosome panel. The twinning /HOMP rate was similar in the PGD5 vs. the PGD9/10 group, failing to show an adverse effect of increase in number of embryos transferred. Therefore, PGD using a 9/10 chromosome panel offers little added value over a 5 chromosome panel with a potential adverse effect on pregnancy rates.