Potential Value of Blastocyst Cultured ContinuaUy from Surplus Embryo

Objective;To explore the significance of in vitro blastocyst development for the surplus embryos after embryos transferred or frozen during IVF/ICSI - ET cycles.Methods;D3 unhigh quality of surplus embryos after high quality embryos transferred and vitrified freezing from IVF - ET cycles were cultured to blastocyst by the sequential method,then the high quality blastula were vitrified freezing.Its were thawed and transplanted in the next cycle of unpregnant patients,It was compared between frozen - thawed embryo of D3 cleavage stage and blastula stage about implantation rate,clinical pregnancy rate,single rate and multiples ratio.Results; A total of 1842 surplus embryos whose infertilities patients of 422 cycles were transplanted and frozen were formed 437 blastulas(23.72%),among which 315 were high quality blastulas(17.10%);The high quality blastulas were vitrified freezing.It were transplanted 42 cycles to frozen 62blastulas in the next cycles,the implantation rate(41.94%) was significant higher than 536 thawing frozen embryos of 243 patient transplanting in D3 cleavage stage(20.90%)(P 0.01 );The clinical pregnancy rate(54.76%) was higher in D3 cleavage stage(36.63%)(P0.05);But No statistically differences existed in regard to single(71.26%vs 85.71%) and mulliples(28.74%vs 13.64%)(P 0.05 );Conclusion:Extending culture can sort out the embryos with development potential from those remnant embryos,maximizing the use of embryos,improving useful embroys and clinical pregnancy rate.