Study On The Relationship Between The Number And Grade Of Embryo Transfer And Pregnancy Outcome In Assisted Reproductive Technology

Objective:To explore the relationship between the number and grade of fresh cycle embryo transfer and pregnancy outcome in assisted reproductive technology.Methods:The clinical data of 1 261 cases of fresh transplantation cycles were analyzed retrospectively.Group according to the number of transferred embryos after age stratification（<35years old:group A,single embryo transferred;group B,double embryos transferred;≥35years old:group a,single embryo transferred;group b,double embryos transferred;group c,three embryos transferred）,then each group was divided into subgroups according to the number of grade I embryos transferred.Group A was divided into group A₀ and group A₁（the number of grade I embryos transferred was 0 and 1）.Similarly,group B was divided into group B₀,B₁ and B₂.With the same grouping method,patients aged≥35 years old were divided into group a（group a₀ and a₁）,group b（group b₀,b₁ and b₂）,group c（group c₀,c₁ and c₂）.The differences of pregnancy outcome between each group were compared.Results:In patients under 35 years old,the clinical pregnancy rate and implantation rate of group A₁ were significantly higher than thoseof group A₀（P<0.05）.The implantation rate,clinical pregnancy rate,multiple pregnancy rate and live birth rate of group B₂ were significantly higher than those of group B₀ and B₁（all P<0.05）.Meanwhile,the clinical pregnancy rate of group B₀ was higher than that of group A₀,the implantation rate of group A₁ was higher than that of group B₁,and the multiple pregnancy rate was lower than that of group B₁（P<0.05）,and there was no significant difference in other indexes between the groups（all P>0.05）.（2）In patients aged 35 years or older,the implantation rate,clinical pregnancy rate and live rate of group a₁ were significantly higher than those of group a₀（all P<0.05）.The clinical pregnancy rate and live birth rate of group b₁ and b₂ were higher than that of group b₀,the implantation rate of group b₂ was higher than that of groupb₀（P<0.05）.The implantation rate and clinical pregnancy rate of group c₂were significantly higher than those of groupc₀ and c₁,however,the multiple pregnancy rate and live birth rate were only higher than those in group c₀（P<0.05）.Meanwhile,the multiple pregnancy rate of group c₂ was significantly higher than that of group b₂（P<0.05）,and there was no significant difference in other indexes between the groups（P>0.05）.Conclusion:In fresh embryo transfer cycle,individualized embryo transfer program should be implemented according to the number and grade of patients’embryos.It is suggested that no more than 2 embryos and no more than 1 embryo of grade I should be transferred at any age.For patients with conditions,single embryo transfer can not only ensure the clinical pregnancy rate,but also effectively reduce the multiple pregnancy rate.