Day 3 Biopsy and Blastulation Rates.

Objective: To determine if blastomere biopsy affects the rate of blastulation as compared to intact embryos.

Study Design: Retrospective age-matched cohort study.

Results: Forty-one patients with 41 in vitro fertilization (IVF) cycles and 329 embryos who under- went cleavage-stage biopsy with preimplantation genet- ic screening using array com- parative genomic hybridiza- tion were compared to 41 IVF cycles with 352 embryos eligible for biopsy but who did not undergo biopsy January 2011-July 2013. The proportion of embryos that developed to the blastocyst stage was significantly lower in the case group than in the control group (46.5% vs. 59.9%; p=0.0134). This was most evident in the age group >35 years old (43.2% vs. 58.8%; p=0.035). No significant difference was detected in proportions that developed to fully expanded' or hatching blastulation between cases and controls (28.0% vs. 24.4%, p=0.56). There was a statistically .significant difference in the proportion of euploid embryos available for transfer when comparing day 3 vs. day 5 biopsy (20.9% vs. 13.1%, p=0.0003).

Conclusion: Cleavage stage biopsy for genetic testing lowers the overall proportion of embryos that develop to the blastocyst stage by 25% (from 59.9% to 46.5%). When compared to trophectoderm biopsy, cleavage stage biopsy allows for a larger cohort of euploid embryos to be available for selection and transfer.