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

Objective: The objection is to analysis the factors which influence theimplantation rate, clinical pregnancy rate, abortion rate in frozen-thawedembryo transfer(FET) cycle.Methods:498FET cycles from Jan.2012to Aug.2013in the forthhospital of Hebei Medical University were collected to performed the study. Aretrospective analysis of the relationships between the influence factors suchas age, BMI, different preparing endometrial protocols, endometrial thicknesson transferred day, serum E2level on ET day, number of embryo transferred,fertilization method and the implantation rate, clinical pregnancy rate andabortion rate.Results: There were1177thawed embryos transferred totally from498FET cycles. The average embryos transferred per cycle was2.36±0.59. Thenumber of embryos implanted was348. The implantation rate was29.57%.The pregnancy cycles were253; the ectopic pregnancy cycls were8; themultiple pregnancy cycles were4; the abortion cycles were26. The clinicalpregnancy rate is49.20%. The ectopic pregnancy rate is3.27%. The multiplepregnancy rate is1.63%. The abortion rate is10.61%.Endometrial preparation protocols: There were4clinical protocols inendometrial preparation including natural cycle, ovulation cycle, HRT cycleand down reglulation combined HRT cycle. The implanation rate in naturalcycle was significant lower than the other cycles (P<0.05).The clinicalpregnancy rate in narural cycle was significant lower than the ovulation cycleand down reglulation combined HRT cycle (P<0.05) and there was nosignificant difference between natural cycle and HRT cycle. There was nosignificant difference in abortion rate among the four clinicalprotocols(P>0.05). Endometrial thickness: The endometrial thickness ranged from7mm to23mm and the average thickness was11.10±2.63mm.4groups were dividedaccording to the endometrial thickness:<8mm group,8-11.9mm group,12-15.9group and≥16mm group. There were no significant difference in implanationrate and clinical pregnancy rate among these four groups(P>0.05). Theabortion rate in <8mm group was much higher than the other groups, but therewas no significant difference among the four groups(P>0.05).Serum of E2level on ET day: E2was divided into2groups to discussaccording to the resources. The E2of natural cycle and ovulation cycle wassecreted by body itself, though the E2of the HRT cycle and the downreglulation cycle was from exogenous supplement. In the the natural cycle andthe ovulation cycle, the E2was divided into three groups,<110pg/ml,110-330pg/ml,>330pg/ml. There was no significant difference in implanationrate, clinical pregnancy rate and abortion rate among the three groups(P>0.05).In the HRT cycle and the down reglulation combined HRT cycle, the E2wasdivided into another three groups,<260pg/ml,260-1330pg/ml,>1330pg/ml.There was no significant difference in implanation rate and clinical pregnancyrate among the three groups(P>0.05) and there were significant differencebetween the group of <260pg/ml and the other two groups(P<0.05).Age: The embryo implanation rate and clinical pregnancy rate in olderthan35years was significant lower than the other two groups(P<0.05). Therewas no significant difference in abortion rate among the three groups(P>0.05).BMI: The BMI range from15.63kg/m2to38.57kg/m2and the averageBMI is23.27±3.51kg/m2.4groups was divided according to the BMI,<18.5kg/m2、18.5-24kg/m2、24-27kg/m2、≥27kg/m2and there was nosignificant difference among the four groups in implanation rate, clinical rateand abortion rate(P>0.05).The number of embryo transfer per cycle: There were3groups accordingto the number of embryo transfer per cycle. There was no significantdifference among the three groups in embryo implanation(P>0.05). Thepregnancy rate of3embryo group is higher than the other groups, but there was no significant difference in these three groups. There was no abortion inthe cycle of1embryo implanted, and there was no significant differencebetween the other two groups(P>0.05).Fertilization method: There were no significant difference between theIVF and ICSI in the embryo implanation rate, clinical pregnancy rate andabortion rate(P>0.05).Logistic regression analysis of clinical pregnancy concerned factorsshowed that: the endometrial thickness, number of embryo transfer per cycleand age had significant influences to the clinical pregnancy. Endometrialpreparation protocols, BMI, fertilization method had no significant influencesto the clinical pregnancy.Conclusions:1Among these factors studied, age, endometrial thickness, number ofembryo transfer per cycle has significant influence to the result of FET.2BMI, fertilization methods has no significant influence to the result ofFET.3The protocol of down reglulation combined HRT cycle have higherclinical pregnancy rate. This protocol may be a better method in endometrialpreparation, but further studies are still needed.4There is no influence in the implanation, clinical pregnancy and theabortion in ICSI. It’s an important and usful method in male infertility, but thepotential risk should be cautioned and use it prudently.