Clinical value of frozen-thawed embryo transfer of intracytoplasmic sperm injection for patients with fertilization failure in conventional in vitro fertilization

Objective:To evaluate the clinical value of frozen-thawed embryo transfer of intracytoplasmic sperm injection(ICSI) for rescuing of conventional in vitro fertilization(IVF) failure.Methods:93 unfertilized MⅡoocytes in 12 women with conventional IVF failure were performed rescue ICSI(Late ICSI) at 18 hours after conventiona fertiliazation in our center,then good quality embryos were frozen and transferred after thawing three monthes later.Results : 63 oocytes out of 93 unfertilized MⅡ oocytes were fertilized after Late ICSI,the rates of fertilization,cleavag and good-quality embryo were 67.7%(63/93),95.0%(57/60) and 43.9%(25/57),respectively,three abnormal fertilization was observed out of 63 fertilized egg(two with mono-pronucleus,one with three pronuclei).25 good quality embryos were cryopreserved by the methods of vitrification in six patients and slow-freezing in other four patients.Eighteen embryos were transferred into uterine cavity in nine women after thawing,one patient failed to receive embroy transfer due to poor quality embryos after thawing.Two patients had documented clinical pregnancies with 22.2%(2/9) clinical pregnancy rate per ET,one had given a healthy live birth by uterine-incision,the other has ongoing pregnancy at the 14th week(?).Conclusion :Late ICSI could be used to reinseminate unfertilized MⅡoocytes in fertilization failure IVF cycles,freezing-thawing embryo transfer from Late ICSI could reduce cycle cancellation rate per oocyte retrieval and obtain a relative satisfactory clinical pregnancy rate by synchronizing embryo development and endometrial receptivity.