Clinical value of transferring frozen-thawed Day-3 non-top quality embryo

Objective:To analyze the clinical value of transferring frozen-thawed non-top quality embryo.Methods:The data of 346frozen-thawed embryo transfer(FET)cycles were analyzed retrospectively.All the cycles were divided into two groups according to the quality of Day-3embryo:top quality embryo group(202cycle)and non-top quality embryo groups(144cycles).The pregnancy and implantation rate and other affecting factors were compared between the two groups.The results of non-top quality embryos after thawed and cultured were observed.Results:The age of the women in the non-top quality embryo group was significantly higher than that of the top quality group [(32.08±4.39)vs.(30.48±4.23)years](P0.05).The undeveloped embryo rate in the non-top quality embryo group was significantly higher than that of the top embryo group(26.54% vs.15.52%),while the blastocyst formation rate(0.62% vs.4.10%),the implantation rate(13.66% vs.30.28%),and the clinical pregnancy rate(26.67% vs.51.55%)were all significantly lower(P0.05).In 135 FET cycles of non-top quality embryo,322 embryos were transferred.The survival rate of 5Bembryos after thawing was significantly higher than that of 4Bembryos(100% vs.91.87%)(P0.05).The undeveloped embryo rate in 5Bembryo group was lower than that in 4Bembryo group(22.86% vs.32.53%),but there was no significant difference(P0.05).Conclusions:Age is one of risk factors for embryo quality and clinical outcome of assisted reproductive technology.Some non-top quality embryos have potential to develop further.It is worthy to freeze and transfer non-top quality embryos for the patients with few or no high quality embryos,which can improve the cumulative pregnancy rate,especially for 5Bembryos.