Reanalyzing of "No Result" Embryos in PGD Cycles by Second Biopsy at Blastocyst Stage

Introduction
In preimplantation genetic diagnosis (PGD) certain embryos fail the genetic testing. Some of those “no-result" embryos are actually healthy, reanalyzing them might increase the chance to get unaffected embryos.

Aim
To determine the diagnostic efficacy of “no-result” embryos at the time of their first PGD with their status after reanalysis.

Methods & Materials:
Embryos on day-3 were subjected to biopsy. One blastomer from each was removed into PCR tubes and transferred to the Genetic Laboratory (Shaarei Zeddek MC Israel). A multiplex nested PCR reaction was used. “No-results” embryos and blastocysts on day 4- 6 were biopsied before vitrification. The biopsied cells were treated the same way as biopsied blastomers, and were immediately vitrified using open system with Sage Media.

Results
The study included 44 patients and 105 PGD cycles. 763 embryos were subjected for PGD. 285 (37%) were not affected and 303 (40%) were affected. The average number of healthy embryos transferred was 1.9±0.47, with a pregnancy rate of 26.5% (22/83).175 (23%) embryos failed the first PGD analysis. 24 "no result" embryos from 13 cycles were re-biopsied before vitrification. 12 embryos on day 4, 7 and 5 blastocysts on day-5 and 6 respectively. We obtained 7 healthy, 8 affected and 9 (38%) recurrent “no-result” embryos . 5 patients have decided to warm their embryos. 6 biopsied blastocyst were thawed, 6 of them survived fully intact and 1 clinical pregnancy was obtained.

Conclusion
Our preliminary data indicate that reanalysis of blastocysts developed from "no result" PGD embryos may achieve additional pregnancies.