Abstract
Background The number and the quality of embryos transferred are important predictors of success in in vitro fertilization (IVF) cycles. In the presence of more than one good quality embryo on the transfer day, double-embryo transfer (DET) can be performed with these embryos, but generally, different quality embryos are present in the available transfer cohort. We aimed to investigate the effect of transferring a poor quality embryo along with a good quality embryo on IVF outcomes. Methods In this study, 2298 fresh IVF/intracytoplasmic sperm injection (ICSI) cycles with two good quality embryos (group A), one good and one poor quality embryo (group B), and single good quality embryo (group C) transfers were examined. All groups were divided into two subgroups according to the transfer day as cleavage or blastocyst stage. Clinical pregnancy and live birth rates were the primary outcomes. Results In the cleavage stage transfer subgroups, the clinical pregnancy rates were lower in the single-embryo transfer (SET) subgroup compared with DET subgroups, but the difference was not statistically significant compared with DET with mixed quality embryos. The live birth rates were comparable between the three groups. In the blastocyst transfer subgroups, the clinical pregnancy and live birth rates were significantly higher in DET with two good quality embryos than DET with mixed quality embryos and SET groups. Multiple pregnancy rates were higher in both DET groups in terms of transfer day (p = 0.001). Conclusion DET with mixed quality embryos results with lower clinical pregnancy and live birth rates compared with DET with two good quality embryos at the blastocyst stage. At cleavage stage transfer, there is no difference in live birth rates between the two groups.