Does human oocyte cryopreservation affect equally on embryo chromosome aneuploidy?

ABSTRACT

Oocytes cryopreservation as an important part of assisted reproductive technologies, which should ensure after warming not only intact oocyte morphological characteristics, but also their genetic apparatus stability. However, the meiotic spindle is very sensitive to the temperature fluctuations that can lead to unequal chromosome segregation during meiosis and as a consequence can cause embryo aneuploidy after oocyte fertilization. The aim of the study was to estimate the oocytes cryopreservation impact on human embryo chromosome aneuploidy. It has been shown that fertilization rate of the cryopreserved oocytes did not differ from fresh ones (83.1% vs 84% respectively). The number of blastocysts obtained from cryopreserved oocytes was less than that obtained from fresh oocytes, however, their morphological characteristics were better if compared the fresh oocytes. Our results showed different cryopreservation impact on aneuploidy rates of certain chromosomes in embryos obtained from cryopreserved oocytes. They had an increased aneuploidy of chromosome 13 and a decreased nondisjunction of chromosome 18 and sex chromosomes.