Transferring two grades I cleavage-stage embryo might not be a good protocol

Purpose: The aim of this study was to explore whether transferring two grades I cleavage-stage embryo was suitable for the patients in the first fresh transfer.Methods: This study included 202 single grades I cleavage-stage, 229 single grades III cleavage-stage, 743 single excellent blastocyst, 522 double grades I cleavage-stage, and 596 double grades III cleavage-stage embryo transfers. Main clinical outcomes: clinical pregnancy and twin-pregnancy rate.Results: Among single excellent blastocyst, single grades I and single grades III group, the clinical pregnancy rate was significantly higher in single excellent blastocyst group than single grades I and grades III group (67.16% versus 42.08% versus 23.97%; p<0.001). When transferred double grades I cleavage-stage embryos, the clinical pregnancy rate reached 68.20% which was no significant difference compared with the single excellent blastocyst group (67.16%). However, the twin-pregnancy rate was significantly higher in double grades I group than double grades III and single excellent blastocyst group (43.26% versus 26.70% versus 0.60%; p<0.001).Conclusions: Because of higher twin-pregnancy incidence rate, transferring two grades I cleavage-stage embryo might not be a good protocol. Extended culture to blastocyst-stage could be considered for the patient with only two grades I cleavage-stage embryos.