Implantation potential of mosaic embryos.

Chromosomal mosaicism is a relatively common finding in human IVF embryos. However, the association between mosaicism in trophoectoderm and inner mass cells, the mechanisms involved, and its effects on implantation are far from established. We retrospectively reanalyzed array-CGH results from 1,362 trophoectoderm biopsies. We detected chromosomal mosaicism in 183 blastocysts (13.4%). A decrease in the clinical pregnancy rate when we compared the cycles where only mosaic embryos were transferred (26.9%) vs. euploid embryos were transferred (40.2%) was not statistically different (p = 0.127). Also a tendency to increase the biochemical miscarriage was reported (21.2% mosaic group vs. 12.3% euploid group; p=0.102). Our data suggests that the transfer of some mosaic embryos achieve full term pregnancies. Additional studies are needed to clarify how embryo mosaicism affects the outcomes of the IVF cycles.