Analysis Of Morphokinetic Parameters And Pregnancy Outcomes Using Time-Lapse System

Objective: Compare the embryo development and pregnancy outcomes between time-lapse system(TMS)and conventional incubator.Furtherly explore the relationship between morphokinetic parameters and pregnancy outcomes using time-lapse system,especially the significance in predicting embryo implantion.Preliminary establish a model for optimal embryo selection applied to our centre.Methods: A retrospective analysis of 137 time-lapse treatments(IVF/ICSI)and 182 conventional incubator treatments(IVF/ICSI)performed in our reproduction centre from December 2016 to December 2017.Collect clinical outcomes such as basic information,number of oocytes collected,number of normally fertilized embryos,highquality embryos rate,implantation rate,biochemical pregnancy rate clinical pregnancy rate and so on.Compare the effect of embryo development between time-lapse system and conventional incubator and proceed statistics analysis of morphokinetic parameters(t2、t3、t4、t5、t6、t7、t8、cc2、s2、cc3、s3)in implanted and not implanted embryos.Group parameters in quartiles and apply binomial logistic regression to find parameters related with embryo implantation.Establish multivariate classification model combined with exclusion standard and perform validation eventually.Results:(1)The high-quality embryo rate(71.7% VS 67.5%,P=0.033),blastocyst formation rate(73.9% VS 56.7%,P=0.000),high-quality blastocyst rate(44.5% VS 36.8%,P=0.039)and clinical pregnancy rate(54.5% VS 41.9%,P=0.047)in time-lapse group were significantly higher than conventional incubator group.(2)The pregnancy outcomes had no significant difference between patients with the age ≤30 and patients with the age >30.The clinical pregnancy rate of ICSI group in time-lapse system was higher than in conventional incubator(81.3% VS 43.5%,P=0.020).(3)In all 675 transplanted or cryopreserved embryos of time-lapse system,146 had one or more abnormal division event,in which 16 were considered implantable embryos and transplanted.4 embryos acquired implantation.(4)Through the comparison of morphokinetic parameters,no significance was found between implanted and not implanted embryos in t2、t3、t4、t5、t6、t7、t8、cc2、s2、cc3 and s3.Divide the distribution range of parameters into four intervals and select intervals with the highest implantation rate as the best interval.Significant difference was found in implantation rate between embryos inside and outside the best interval in t6、t7 and cc2.(5)We identified t6、t7 as the best predictors related to implantation via logistic regression method and defined a classification model(with five grades)to predict embryo implantation combined with exclusion standard of abnormal division event.The implantation rate declined with the falling of grades.The area under the ROC curve was 0.649.The model was possiblely predictable for high quality blastocyst.Conclusion:(1)Time-lapse system can improve embryo quality and pregnancy outcomes,especially in ICSI treatments.(2)Time-lapse system can found abnormal division events in embryo development and provide new evidence to exclude embryos.(3)Morphokinetic parameters(t6,t7)are most closely related to implantation potential.An embryo selecting model can be established combining time parameters and exclusion standard,but further validation is still needed.