The impact of pronuclear orientation to select chromosomally normal embryos

Purpose: To find an effective method to select embryos from ICSI with better chromosomal status when preimplantation-genetic-diagnosis (PGD) is not applied. Methods: Several morpholological evaluations were done in same embryos. Embryos from ICSI were classified on day I according to pronuclear-nucleoli arrangement. On day 3, classification was done according to number, fragmentation, size and shape of cells. In some patients, embryos exhibiting good quality on day 3 (at least six regular blastomeres with cell fragmentation lower than 20%) were also submitted to PGD, irrespective to pronuclear-nucleoli morphology. Results: Forty-two per cent of normally fertilized embryos showed pronuclear-nucleoli-good-morphology; from those, 86% were also classified as good quality on day 3. Good-quality embryos submitted to PGD have shown lower chromosomal abnormality rates when also classified as pronuclear-nucleoli-good-morphology. Conclusions: Pronuclear-nucleoli morphology seems to be correlated with PGD results. This criterion may prove useful for pre-select embryos with normal chromosomal package when PGD is not applied.