Assessment of aneuploidy formation in human blastocysts resulting from donated eggs and the necessity of the embryos for aneuploidy screening

Abstract

Purpose To examine the prevalence of aneuploidy in human blastocysts resulting from donated eggs and embryo implantation after transfer of normal euploid embryos. Also, to assess the necessity of preimplantation genetic screening (PGS) for embryos produced with donor eggs. Methods Blastocysts from donor-recipient cycles were biopsied for PGS (PGS group) and the samples were analyzed with DNA microarray. Euploid blastocysts were transferred to the recipients, and both clinical pregnancy and embryo implantation were examined and compared with embryos without PGS (control group). Results After PGS, 39.1 % of blastocysts were abnormal, including aneuploidy and euploid with partial chromosome deletion and/or duplication. Transfer of normal euploid blastocysts brought about 72.4 % of clinical pregnancy, 65.5 % of ongoing/delivery and 54.9 % of embryo implantation rates; these rates were slightly higher than those in the control group (66.7, 54.0 and 47.8 %, respectively), but there was no statistical difference between the two groups. By contrast, the miscarriage rate was higher in the control group (19.2 %) than in the PGS group (9.5 %), but no statistical difference was observed. Transfer of two or more embryos did not significantly increase the ongoing/delivery rates in both groups, but significantly increased the twin pregnancy rates (50.0 % in the PGS group and 43.8 % in the control group). Conclusion(s) High proportions of human blastocysts derived from donor eggs are aneuploid. Although pregnancy and embryo implantation rates were increased, and miscarriage rates were reduced by transfer of embryos selected by PGS, the efficiency was not significantly different as compared to the control, suggesting that PGS may be necessary only in some specific situations, such as single embryo transfer.

Aneuploidy analysis in day 7 human blastocysts produced by in vitro fertilization

“…The proportion of aneuploid embryos increases in women with aging [ 4 – 10 ]. Even in young patients undergoing in vitro fertilization (IVF), it has also been found that high proportions of embryos are aneuploid [ 11 – 14 ].…”

“…Previously it has been found that PGS can increase clinical pregnancy and embryo implantation rates in patients of advanced maternal ages, recurrent miscarriage and previous spontaneous miscarriage, as aneuploidy is the main reason for unsuccessful embryo implantation in these populations of patients [ 9 , 18 – 20 ]. As widespread application of PGS in human IVF clinics, it would appear that PGS may also increase embryo implantation rate in all patients undergoing IVF including young patients and recipients who receive egg donation [ 9 , 10 , 12 , 14 , 19 ], especially when single embryo transfer is performed [ 12 , 14 ].…”

Assessment of clinical application of preimplantation genetic screening on cryopreserved human blastocysts

“…In our previous study, we did not find significant increase in either clinical pregnancy or embryo implantation when blastocysts from donated eggs were screened and transferred, especially when two blastocysts were transferred. As suggested by these authors, unrestricted clinical application of current PGS (either aCGH or NGS) should be avoided [ 30 , 31 , 34 ].…”

Innovations in assisted reproductive technologies: impact on contemporary donor egg practice and future advances

“…Historically, egg donor cycles have resulted in transfer of PGT-untested embryos. While donor oocyte cycles typically result in high pregnancy and live birth rates due to the young age of the donor, prior studies have shown that up to one third of embryos derived from donor oocytes are aneuploid (41,42). In a retrospective cross-sectional study of U.S. data from the Society for Assisted Reproductive Technology Clinic Outcome Reporting System from 2005 to 2013, live birth rates were significantly lower for PGT-A (51.8%) than control cycles (59.9%, P¼ .001).…”