Microarray-Based Comparative Genomic Hybridization testing allows for the detection of aneuploidies, an abnormal number of all 24 chromosomes in human embryos. Through aCGH, each and every chromosome in the embryo is tested, whereas previous PGD tests focused on only a few chromosomes. Embryologists can now combine information gained by routine microscopic examination with the results of aCGH before they select embryos for transfer or freezing.  Normal embryos have a higher chance of implantation, increasing the likelihood of pregnancy, reducing the chances of pregnancy loss, and improving the odds of delivery.