Potential use of repeated fluorescence in situ hybridization in the same human blastomeres for preimplantation genetic diagnosis

Objective: To assess the feasibility of repeated fluorescence in situ hybridization (FISH) procedures in the same nucleus of a human blastomere. Design: Three consecutive FISH procedures were performed in the same human blastomere by using direct label fluorescence CEP and WCP probes (Vysis). Setting: Hospital-based private IVF program. Patient(s): Twenty-eight infertile couples who underwent conventional IVF in our center. Intervention(s): Embryos from oocytes with three pronuclei after in vitro insemination were used in this study. Main Outcome Measure(s): The rates of nuclear loss, present signals, and absent signal were examined. Result(s): In group 1, the rates of presence of signals were 94% after the first FISH, 92% after the second FISH, and 88% after the third FISH. In group 2, the rates of presence of signals were 96% after the first FISH, 93% after the second FISH, and 87% after the third FISH. There was no statistically significant difference in the rates of nuclear loss, present signals, and absent signal between three consecutive FISH procedures and between CEP and WCP probes. Conclusion(s): Six or more chromosomes of a single blastomere may be examined with use of this repeated FISH procedure, which may be important for preimplantation genetic diagnosis.