What is the Likelihood of Success for Biopsied Day 5 Embryos That Have Not Achieved Blastocyst Formation?

Abstract

Background and Significance: Typically blastocyst formation occurs by day 5, post oocyte retrieval. In situations where an embryo has not formed a blastocyst by day 5, many groups will not consider those embryos for transfer. We now present data that suggests that embryos that have undergone preimplantation genetic diagnosis (PGD), that have not reached blastocyst formation by day 5 still have a reasonable likelihood for implantation and achievement for successful pregnancy.Objective: In an effort to determine the viability of day 5 embryos that have not formed blastocysts, we retrospectively reviewed 36 pregnancies achieved through PGD in our program.Materials & Methods: All patients underwent controlled ovarian hyperstimulation (COH) protocols using either Lupron for down regulation or Antagon to block LH. At the appropriate time hCG 10,000 IU was administered and ultrasound guided oocyte retrieval was performed. Intracytoplasmic sperm injection (ICSI) was performed on all mature oocytes. Embryo biopsy and blastomere fixation was performed on day 3 post retrieval on all 6-8 cell embryos. Slides were then sent to Reprogenetics for fluorescence in situ hybridization (FISH) analysis for chromosomes 13, 15, 16, 17, 18, 21, 22, X and Y. Results were received day 4-5 post retrieval. Embryo transfer of only the chromosomally normal embryos was done on day 5 post retrieval. The results are shown below:Tabled 1BLASTOCYSTNON- BLASTOCYSTTOTALEmbryos transferred31/67 (46.3%)36/67 (53.7%)67 (100%)Embryos implanted22/41 (53.7%)19/41 (46.3%)41/67 (61.2%) Open table in a new tab Conclusions: From the data, the following conclusions may be made: 1.) Biopsied embryos transferred on day 5 that were not blastocysts achieved successful pregnancies. It is possible that the biopsy procedure may delay development in some embryos, as it has already been reported in the past (Hardy et al. 1990). However, the delay does not appear to be jeopardizing the embryos potential for implantation and ultimate successful outcome. 2.) Biopsied embryos that were blastocysts on day 5 had a slightly higher likelihood for implantation. 3.) Based on these results, patients should be encouraged to transfer previously biopsied embryos with normal karyotypes, regardless of whether or not the embryo has reached the blastocyst stage. Background and Significance: Typically blastocyst formation occurs by day 5, post oocyte retrieval. In situations where an embryo has not formed a blastocyst by day 5, many groups will not consider those embryos for transfer. We now present data that suggests that embryos that have undergone preimplantation genetic diagnosis (PGD), that have not reached blastocyst formation by day 5 still have a reasonable likelihood for implantation and achievement for successful pregnancy. Objective: In an effort to determine the viability of day 5 embryos that have not formed blastocysts, we retrospectively reviewed 36 pregnancies achieved through PGD in our program. Materials & Methods: All patients underwent controlled ovarian hyperstimulation (COH) protocols using either Lupron for down regulation or Antagon to block LH. At the appropriate time hCG 10,000 IU was administered and ultrasound guided oocyte retrieval was performed. Intracytoplasmic sperm injection (ICSI) was performed on all mature oocytes. Embryo biopsy and blastomere fixation was performed on day 3 post retrieval on all 6-8 cell embryos. Slides were then sent to Reprogenetics for fluorescence in situ hybridization (FISH) analysis for chromosomes 13, 15, 16, 17, 18, 21, 22, X and Y. Results were received day 4-5 post retrieval. Embryo transfer of only the chromosomally normal embryos was done on day 5 post retrieval. The results are shown below: Conclusions: From the data, the following conclusions may be made: 1.) Biopsied embryos transferred on day 5 that were not blastocysts achieved successful pregnancies. It is possible that the biopsy procedure may delay development in some embryos, as it has already been reported in the past (Hardy et al. 1990). However, the delay does not appear to be jeopardizing the embryos potential for implantation and ultimate successful outcome. 2.) Biopsied embryos that were blastocysts on day 5 had a slightly higher likelihood for implantation. 3.) Based on these results, patients should be encouraged to transfer previously biopsied embryos with normal karyotypes, regardless of whether or not the embryo has reached the blastocyst stage.