RESUMO
OBJECTIVE: To evaluate the survival rate and clinical results of our vitrification procedure on preimplantation genetic diagnosis (PGD) blastocysts and to calculate its actual contribution to the reproductive outcome per cycle. DESIGN: Retrospective clinical study. SETTING: University Institute IVI, Valencia, Spain. PATIENT(S): Patients who requested cryotransfer of surplus PGD blastocysts after failed fresh elective transfer. INTERVENTION(S): Retrospectively collected data during 2 years of experience with blastocyst vitrification. MAIN OUTCOME MEASURE(S): Primary outcome measures were the following: blastocyst recovery and survival; cryotransfer cancellation; and the implantation, pregnancy (PR), and ongoing-pregnancy rates. The secondary outcome measure was cumulative ongoing PR (COPR). RESULT(S): Cocultured vitrified PGD blastocysts were recovered and progressed in development after overnight culture (survival rate) at rates comparable to those of non-PGD blastocysts (49% and 42%, respectively). After transfer to 64% of patients, no statistical differences were found between PGD and non-PGD blastocyst groups concerning the following: PR (44% vs. 37%), implantation rate (40% vs. 27%), and ongoing-pregnancy rate (32% vs. 37%). Moreover, blastocyst vitrification significantly increased the COPR in both PGD and non-PGD cycles, from 47% (62/133) to 53% (70/133) and from 45% (24/53) to 53% (28/53), respectively. CONCLUSION(S): A preimplantation genetic diagnosis blastocyst vitrification procedure showed survival rates and improvements on the COPR that were comparable to those in non-PGD blastocyst cycles. Moreover, vitrification of biopsied and diagnosed embryos at the more advanced stages instead of at earlier cleavage stages is presented as an attractive strategy to consider in PGD programs.
