RESUMEN
Objective To compare the clinical outcomes of two D3 embryo and single blastocyst transfer in patients retrieving different oocytes, so as to provide data support for selecting a clinical transfer strategy. Methods We made a retrospective analysis of patients who underwent in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI)between January and December 2014 in the Reproductive Medicine Center,the Third Affiliated Hospital of Zhengzhou University.The patients were divided into three groups according to the number of oocytes received:Group A (5-9 oocytes),Group B (10 - 14 oocytes)and Group C (≥ 1 5 oocytes).Patients in each group all received four different transfer methods as follows:transfer of two fresh D3 embryos (a ),transfer of one fresh blastocyst (b ),transfer of two D3 frozen embryos (c ),and transfer of one frozen blastocyst (d ).We compared the 2PN fertilization rate of oocytes,rate of available embryos and rate of good embryos among the three groups.We also compared the embryo implantation rate,biochemical pregnancy rate,clinical pregnancy rate, multiplets rate and abortion rate among the four transfer methods in each group.Results ① There were 667, 573,and 479 transfer cycles in Group A,Group B and Group C,respectively.The 2PN fertilization rate of IVF and available embryos rate was significantly higher in Group A than in Group B and Group C (P =0.003/P 0.05),but the implantation rate of c was significantly lower than that of a and d (P =0.027/0.020),d had a higher implantation rate than a and c in Group B (P =0.005/0.001).In Group C,the biochemical pregnancy rate and clinical pregnancy rate of d were significantly higher than those of a (P =0.048/0.027)and c (P =0.003/0.001).Patients in Group C also had a higher implantation rate than D3 embryos (P <0.05).③ The multiple pregnancy rate of single blastocyst transfer decreased compared with D3 embryos transfer in the three groups (P <0.05).Conclusion Single blastocyst transfer has both higher implantation rate and lower multiple pregnancy rate in high response patients (1 5 or more oocytes received).For patients who received 5-9 and 10-14 oocytes,D3 embryos have a similar clinical pregnancy rate with that of single blastocyst but a higher multiple pregnancy rate.Single vitrified-warmed blastocyst transfer has a higher clinical pregnancy rate.It is the best transfer method for patients who received more than 10 oocytes.