Early blastulation of day 4 embryo correlates with the increased euploid rate of preimplantation genetic screening cycles

Abstract

Objective: It is known that embryos with faster growing potential, especially in blastocyst development, correlate with the increased euploid rate. Our study investigated the preimplantation genetic screening cycle to analyze the correlation between early blastulation (EB) on day 4 embryo and the euploid rate. Materials and methods: This is a retrospective study examining 273 biopsied blastocysts after preimplantation genetic screening obtained from 54 patients from March 2013 to March 2017. Of the 273 biopsied embryos, 81 had early blastulation on day 4 and were classified as the EB (+) group, while the other 192 had no early blastulation and were classified as the EB (−) group. Euploid rates were compared between the two groups. A total of 34 single euploid embryos were transferred, with 14 from the EB (+) group and 20 from the EB (−) group. Clinical pregnancy was compared between the groups. Results: There is a statistically significant increase in the euploid rate in the EB (+) group (49.4% vs. 34.4%, p = 0.02). The clinical pregnancy rate was also increased in the single euploid embryo transfer group with early blastulation, but did not reach statistical significance (71.4% vs. 50.0%, p = 0.211). Conclusions: Early blastulation of day 4 embryo correlates significantly with the euploid rate. Early blastulation of day 4 embryo may serve as a potential aid for embryo selection for transfer in preimplantation genetic screening cycles. Keywords: Blastocyst, Embryonic development, Preimplantation genetic screening, Pregnancy rate, Single embryo transfer