Objective: To evaluate the efficiency and efficacy of a simplified two-pipette technique in comparison to the conventional three-pipette method; in the two-pipette method, a single, larger drilling/biopsy pipette is used to perform zona pellucida (ZP) drilling and blastomere aspiration for embryo biopsy.
Design: A preclinical, prospective, randomized, in vitro experiment.
Setting: The reproductive unit of a university teaching hospital.
Patient(s): Ninety-five excess embryos at the two- to four-cell stage were obtained from 35 patients undergoing IVF.
Intervention(s): At the six- to eight-cell stage, 88 embryos were allocated randomly to three groups: group I for the conventional method (n = 29), group II for the simplified technique (n = 30), and group III for controls (n = 29). The embryos then were cultured in vitro. The retrieved blastomeres were fixed and examined with fluorescence in situ hybridization using X and Y probes simultaneously.
Main outcome measure(s): Biopsy time, successful retrieval of a blastomere, fixation of the cell, signals developed from fluorescence in situ hybridization, and growth potential and hatching capacity of the biopsied embryos were evaluated.
Result(s): The mean time (+/- SD) for biopsy of each embryo in group I (435 +/- 137 seconds) was significantly longer than that in group II (126 +/- 32 seconds). The success rates for obtaining an intact blastomere were not different between group I (93%) and group II (97%). The growth capacity to the blastocyst stage was similar among the three groups (34%, 37%, and 38%, respectively). However, the ZP-drilled and biopsied embryos of groups I and II had higher percentages of hatching (34% and 37%, respectively) and complete hatching (17% and 20%, respectively) than did those of group III (10% and 0, respectively). The blastomeres obtained by biopsy in groups I and II were equally fixed (90% vs. 90%, respectively) and shown in fluorescence in situ hybridization (79% vs. 80%, respectively).
Conclusion(s): Compared with the conventional method, the simplified technique is more efficient and equally efficacious for blastomere biopsy in preimplantation genetic diagnosis.