Array comparative genomic hybridization: its role in preimplantation genetic diagnosis.

PURPOSE OF REVIEW Embryo assessment is a crucial component to the success of IVF. A high rate of embryos produced in vitro present chromosomal abnormalities and have reduced potential for achieving a viable pregnancy. The use of preimplantation genetic diagnosis by array comparative genomic hybridization, for comprehensive aneuploidy screening of embryos, to improve IVF outcomes, is reviewed. RECENT FINDINGS Data from comprehensive aneuploidy screening of embryos showed that aneuploidies may occur in any of the 24 chromosomes, indicating that aneuploidy screening of all chromosomes is necessary to determine whether an embryo is chromosomally normal. Initial studies on clinical application of this technology have documented improved pregnancy outcomes following transfer of screened embryos. The optimal stage of preimplantation development at which preimplantation genetic screening (PGS) should be performed still remains to be determined. SUMMARY Although clinical results have been promising, further evidence is required to establish whether PGS results in enhanced live birth rate, and if this is the case, to identify which patients may benefit from the procedure. The results from several ongoing randomized controlled trials, performed at different cell biopsy stage and categories of patients, will provide the data needed to accept or reject the clinical efficacy of PGS.