Dados do Trabalho

Title

Morphology and embryo development day evaluation as a criteria in single euploid blastocyst transfer cycles

Objective

Evaluate if embryo development day (D+5 or D+6) and its morphology impact on clinical pregnancy rates in single blastocyst transfer cycles.

Methods

Cross-sectional study performed from January 2019 to December 2022 including couples that went through assisted reproduction treatments associated with embryo genetic study (PGT-A) with single blastocyst transfer. Blastocysts were evaluated according to: day of development – Day 5 (D+5) or Day 6 (D+6); trophectoderm morphological score (top quality – AA, AB, BA; intermediate – BB and poor – BC, CB, CC), considering grade 3 or superior expansion. 365 embryos were studied and submitted to 3 different comparatives analysis. 1: poor quality blastocysts achieving on D+5 (n=183) versus D+6 top quality (n=43); 2: D+5 poor quality embryos (n=183) versus D+6 intermediate quality (n=30) and 3: D+5 intermediate quality embryos (n=109) versus D+6 top quality (n=43). The endpoint of this study was clinical pregnancy rate evaluation.

Results

The clinical pregnancy rate found when groups were compared was 45% and 50% respectively (p=0,754) in analysis 1; 45% and 40% (p=0,584) in analysis 2 and 54% and 50% (p=0,785) in analysis 3. There were no statistically significant differences on those analysis.

Conclusion

Embryo chromosomal status is still the gold standard criteria for embryo selection.
When D+5 top quality euploid embryos are available, these are still the priority choice for embryo transfer. However, to couples that don’t dispose better quality blastocysts, the results obtained in this study showed no difference in clinical pregnancy rates when embryo development day is compared with poor quality embryos. The authors understand that complementary studies with higher casuistry are appropriate to solidify the statistical relevance.

Keywords

Blastocyst, euploid, clinical pregnancy.