Implantation rates in patients with and without PGD.

Introduction: Preimplantation genetic diagnosis (PGD) by detecting aneuploidy, allows us to choose healthy embryos for transfer, thus reducing miscarriage rates. By the same token, PGD should also theoretically produce an increase in implantation rates (IR). There is also a possibility that the process of biopsy might in fact help in embryo hatching and thus increase the implantation rate of the embryos. On the other hand the possible benefit might be countered by the stress encountered by the embryos itself during biopsy and handling. The objective of this study was to evaluate the IR for embryos that had PGD compared with those without PGD. Materials/Methods: This was a retrospective review. The embryos from all patients undergoing ART in the TMC Fertility Centre, Malaysia (formerly Damansara Fertility Centre, Malaysia) from 1 January to 31 December 2006 were included in this study. Since aneuploidy rates increase with age, patients were divided into two age groups, patients aged <38 years compared with those ge;38 years. PGD was either performed on day 3, day 5 or day 6. In the cleavage stage embryos, only one blastomere was biopsied, whereas in the blastocysts, 3-5 trophectoderm cells were biopsied. All specimens were fixed and hybridized for aneuploidy screening for chromosomes 13, 16, 18, 21, 22, X and Y. Embryos with no abnormalities detected by PGD were selected for transfer. The authors defined IR as the number of gestational sacs seen on ultrasonography among all the embryos that were transferred into the uterus. Results: The mean age was comparable for patients aged <38, i.e. 32.3 (PGD) and 31.9 (non-PGD). Similarly the mean age was also comparable for patients aged ge;38, i.e. 40.1 versus 40.4 for the PGD and non-PGD groups, respectively. A total of 1224 embryos were analysed. Of these, 91 embryos had PGD while the remaining 1133 embryos did not undergo PGD. PGD was done for 71 embryos in the <38 age group and 20 embryos in the ge;38 age group. The IR in the PGD group was significantly higher than in the non-PGD group (44% versus 28.2%; P < 0.05). When stratified for age, in patients aged <38 the IR was significantly higher in the PGD group compared with the non- PGD group (49.3% versus 33.1%; P < 0.05). In the ge;38 age group, there was no significant difference in the IR between the two groups (25% versus 15.3%; P = 0.195), although there was a trend towards higher IR in the PGD group. It is possible that in the ge;38 age group, the failure to demonstrate statistical significance could be due to the small sample size. Conclusions: The IR for embryos with PGD were higher compared with those without PGD. [ABSTRACT FROM AUTHOR]