Objective: To select chromosomally euploid embryos for transfer by analyzing single biopsied blastomeres using either fluorescence in situ hybridization (FISH) for chromosomes 13, 16, 18, 21, and 22 or comparative genomic hybridization (CGH), which provides a full karyotype.
Design: Prospective observational study.
Setting: A large IVF unit and the research laboratory of a hospital clinical genetics unit.
Patient(s): Twenty patients with recurrent implantation failure.
Intervention(s): Ovarian stimulation and IVF by intracytoplasmic sperm injection (ICSI), embryo biopsy, and embryo transfer.
Main outcome measure(s): Chromosome normality of biopsied blastomeres and implantation and clinical pregnancy rates.
Result(s): Comparative genomic hybridization was able to identify many chromosomal abnormalities that would have been missed if those cells had been analyzed by FISH. The clinical pregnancy rate per transfer and implantation rate was 11% and 7% for embryos analyzed by FISH and 21% and 15% for embryos analyzed by CGH.
Conclusion(s): Comparative genomic hybridization is more effective than FISH for identifying chromosomally normal embryos, which may result in a higher clinical pregnancy rate and implantation rate after embryo transfer.