Editorial: Poor Quality Embryos Hamper the Development of High Quality Ones

Embryo quality and embryo selection are critical criteria for embryo transfer and subsequently success of assisted reproductive technologies (art). transfer of good quality embryos is associated with increased implantation, pregnancy and live birth rates and also decreased pregnancy loss and prenatal complications in comparison with transfer of embryos with impaired quality. furthermore, advance in embryo culture techniques and embryo selection criteria and technologies lead to a decrease in number of transferred embryos without significant decline in art success. therefore, elective single embryo transfer (eset) is recently the dominant discourse in the community and infertility clinics. an important concern of eset is reduced multiple pregnancy and its prenatal complications as a major complication of art. since more than one embryo is produced in ivf cycle, surplus embryos with appropriate quality are frozen for future transfer in frozen/thawed cycles. there are treatment cycles in which the number and quality of embryos are not sufficient for freezing/thawing. the question always arises in these cycles is that does simultaneous transfer of low and top quality embryos have determining impact on treatment success or not?. it was previously believed and recent finding reported that the low quality embryos have no impact on implantation and development of top quality embryos; even, many low quality embryos have the potential for implantation and successful pregnancy. as a result, twin pregnancy is 9.5% in cycles with transfer of one top quality and one low quality embryo; however, it is zero in eset and 10.6% in cycles with two top quality embryos (1).