Embryo growth rate in vitro as an indicator of embryo quality in IVF cycles

Purpose: The role of embryo growth rate in vitro as an isolated indicator of embryo quality in IVF was evaluated retrospectively. Methods: Comparison was made between 98 cycles (group 1), in which only embryos at a cleavage stage of two to three blastomers were transferred, and 99 cycles (group 2), in which all embryos were transferred at a cleavage stage of four or more blastomers. Embryos were transferred at a fixed interval of 42 to 44 h following oocyte insemination. The mean patients' age, number of oocytes recovered and number of embryos transferred per cycle were similar in both groups. Results: The pregnancy rate and the take-home-baby rate were significantly higher in group 2 as compared to group 1 (22.2% vs 7.1% and 16.2% vs 4.1%; P <0.05 and P <0.01, respectively). Conclusions: These results demonstrate that embryos with a slow cleavage rate in vitro are less likely to produce pregnancy following IVF-ET and that the cleavage stage is a valuable criteria in the selection of the best embryo for transfer.