Analysing the factors that influence the clinical outcomes of the frozen thawed embryo transfer

Objective: To investigate the factors influencing the prognosis of frozen thawed embryo transfer(FET) cycles.Methods: This is a retrospective study analyzing 570 FET cycles.Analysing the influence of the female age,embryo quality,embryo transfer numbers and endometrial thickness on pregnancy rate,implantation rate,ongoing rate,early abortion rate,multiple pregnancy rate.Results:Through logistic regression analysis,we found that the female age,the embryo numbers of transferred and the numbers of high quality embryos transferred,shows close correlation with clinical pregnancy.It appeared a downtrend of pregnancy with the age.The pregnancy rate(49.4%) of patients' age35 were higher than patients' age≥35(37.9%).The quality of embryos,especially the numbers of high quality embryos transferred,shows close correlation with FET outcomes.When two embryos were transferred,the pregnancy rate(49.3%) were higher than one embryo(15.4%).When three embryos were transferred,while the pregnancy rate were similar(50.0%).When≥1 good embryos were transferred,the pregnancy rate(58.0%) were higher than one embryo(37.5%).Conclusion:The female age and the embryo quality of transferred,shows close correlation with FET outcomes.