The impact of in-vitro maturation of oocytes on aneuploidy rate

Chromosome abnormalities in embryos obtained through in-vitro maturation (IVM) of oocytes from 11 oocyte donors were compared with embryos from women undergoing fluorescence in-situ hybridization (FISH) analysis for sex selection. Thirty-three oocytes had reached metaphase II stage at 28–30h (65%) and 27 were successfully fertilized by intracytoplasmic sperm injection. Blastomere biopsy was performed in 20 embryos (74%). For five embryos, two blastomeres were analysed, three of which were mosaic. FISH study revealed aneuploidies of chromosomes 13, 15, 16, 18, 21, 22, X and Y in 12 embryos (60%) and euploidy in the remaining eight (40%). The percentage of aneuploidies in the control group was 33%. Differences between IVM and control embryos were not statistically significant. The high incidence of chromosome abnormalities in embryos resulting from the IVM protocol may account for the low implantation rates reported by others. Although a greater incidence of miscarriage or congenital abnormalities in babies born alive following IVM versus conventional IVF has not been observed in previous studies, preimplantation genetic aneuploidy screening or prenatal chromosome studies may be recommended to these patients on the basis of the present results.