Received April 18, 2017
Accepted July 10, 2017

Objective: This work aims to increase the knowledge of monopronucleated ICSI-derived blastocysts analyzing trophectoderm biopsies by aCGH and FISH in order to evaluate their chromosome constitution. Methods: Fifteen monopronucleated ICSI-derived blastocysts were studied. Double trophectoderm biopsy was performed and analyzed by FISH and aCGH. Blastocysts were classified according to chromosome constitution. Discordances between the two techniques were assessed. Results: Results obtained after FISH and aCGH analysis showed the following: 20% (3/15) and 60% (9/15) diploid females, respectively; 26.7% (4/15) and 26.7% (4/15) diploid males, respectively; and 53.3% (8/15) and 13.3% (2/15) mosaics, respectively. No mosaic male embryos were observed by FISH or aCGH. Discordances were observed in 40% (6/15) of the cases due to the higher detection of mosaicism by FISH compared to aCGH. Conclusions: The combination of FISH and aCGH has been shown to be a suitable approach to increase the knowledge of monopronucleated ICSI-derived embryos. FISH analysis of blastocysts derived from monopronucleated ICSI zygotes allowed the conclusion to be drawn that aCGH underestimates haploidy. Some diploid embryos diagnosed by aCGH are in fact mosaic. In cases where these embryos would be used for reproductive purposes, extra analysis of parental genome origin is recommended.