Analysis Of Factors Influencing The Results Of Frozen-thawed Embryo Transfer

Background and ObjectivesThe first Frozen-thawed embryo transfer of mice got success and born in1972.In1985, the world’s first human Frozen-thawed embryo transfer (FET) succeeded anda healthy baby born. After that, rapidly developed in the field of assisted reproductive.At present, the Frozen-thawed embryo transfer technology has become an importantpart of the assisted reproductive technology, the factors that influence frozen-thawedembryo transfer has become an explored and research hot spot. But, a lot of researchresults have still been disputed. Previous studies mostly analyze the single factor or asingle frozen method, this study combined with vitrification freezing andprogrammed freezing period, and also from two aspects of the factors of embryosalive and clinical indicators to analyze the factors influencing the clinical outcome offrozen-thawed embryo transfer.MethodsA total of1255cycles of frozen-thawed embryo transfer related informationwere retrospectively analyzed in January2009-December2013, The embryos werefrom Reproductive center in the second affiliated hospital of Zhengzhou university,which include468frozen cycles,787stylized vitrification freezing cycles. Grouping method:1. The freezing methods were vitrification freezing group and programmedfreezing group2. The range of patients’ age was20to45year, we divided it into <30y group,30~35y group,>35y group3. The fertilization methods were in vitro fertilization group and Intracytoplasm-ic single sperm injection group.4. The range of the time of cryopreserved embryos was30to1080days, wedivided it into four groups (<180days,181~360days,361~720days,≥721days)The clinical informations of787stylized vitrification freezing cycles analyzedretrospectively. Grouping method:1. The range of patients’ age was20to45year, we divided it into <30y group,30~35y group,>35y group2. There have three methods for preparing endometrial: natural cycle group,hormone replacement therapy (HRT) cycle group, ovarian stimulation cycle group.3. We divided three groups according to the number of transferred embryos: oneembryo group, two embryos group, three embryos group.4. We divided four groups according to embryo transfer distance to the fundus(TDF):<1.0cm group,1.0~<1.5cm group,1.5~2.0cm group,>2.0cm group.Results1. The thawed embryos survival rate of vitrification freezing method, completeembryo survival rate significantly higher than the programmed freezing (P<0.05).2. For different age groups, fertilization methods and embryos survival timethawed embryo survival rate and complete embryo survival rate has no obvious effect(P>0.05).3. Age<30years old group of multiplets rate is higher than age35years oldgroup (P<0.05).4. The embryo grow rate of different endometrial preparation plan, rate of linicalpregnancy, miscarriage, multiplets and ectopic pregnancy has no obvious effect (P>0.05).5. The three embryos group’s implantation rate higher than one embryo group((32%VS17%); The clinical pregnancy rate of three groups have statisticallysignificant(P <0.05); The three embryos group’s multiplets rate higher than the othertwo groups (P <0.05).6. The clinical pregnancy rate of embryo transfer distance to the fundus (TDF)1.5~2.0cm group is higher than TDF<1.0cm group and TDF>2.0cm group (53%VS38%,34%)(P <0.05); The abortion rate of TDF1.5~2.0cm group is lower thanTDF>2.0cm group (14%VS31%)(P <0.05).Conclusion1. The rates of embryo survival and complete embryo survival in Vitrificationfreezing method are higher than programmed freezing method.2. The time of cryopreserved embryos was less than three years, which has noinfluence on the survival of embryos.3.The young patient below30years old could have high risk of multiplepregnancies.4.1.5~2.0cm may be the best transfer distance.