Does a poor-quality embryo have an adverse impact on a good-quality embryo when transferred together?

BACKGROUND: In some in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) cycles, we may consider transferring one poor-quality embryo with one good-quality embryo. Previous studies have indicated that the poor-quality embryo transferred with a good-quality embryo does not negatively affect the clinical pregnancy rate or live birth rate. The purpose of this study was to evaluate pregnancy outcomes and neonatal outcomes in this context. METHODS: This was a retrospective study that included 1646 cycles from our centre. Patients were divided into two groups (group A: one good-quality embryo was transferred with one poor-quality embryo; group B: two good-quality embryos were transferred). The primary outcomes were the clinical pregnancy rate and live birth rate. Additionally, we investigated the implantation rate, ectopic pregnancy rate, abortion rate, multiple pregnancy rate, birthweight and gestational age. RESULTS: We found that there were no differences in the clinical pregnancy rate and live birth rate between group A and group B. However, the implantation rate and multiple pregnancy rate were higher in group B than in group A. CONCLUSIONS: The poor-quality embryo does not have a significant influence on the good-quality embryo when transferred together.