23-chromosome microarray embryo selection does not improve embryo quality in a given cycle of ovarian stimulation. Rather, it allows for the identification and selection of high-quality, "competent" embryos for transfer. As such, Arizona Center for Fertility Studies believes it may dramatically improve the live birth rate per embryo transferred and brings us much closer to a time where single embryo transfers will become standard.
While 23-chromosome microarray testing (as is also the case for FISH-PGD) markedly reduces the risk of numerical chromosomal birth defects such as Down's syndrome, it does not absolutely preclude their occurrence. In fact, the anticipated error rate could be ≤5%. Thus, all women undergoing microarray or FISH egg/embryo selection and who seek absolute confirmation that numerical chromosomal birth defects will not occur should still undergo prenatal genetic testing in the 1st or 2nd trimester.