Does in Vivo Culture of Pre-cleavage Stage Embryo Reduce the Incidence of Aneuploidy? A Sibling Oocyte, Prospective, Multi-centric, Randomized, Open Study, Clinical Study in Subjects With Subfertility Undergoing Assisted Reproductive Medical Treatment

As soon as the very first minute of the fertilization process, very important biological events, critical for the future developmental competency of the embryo are taking place.

These biological events, after the sperm cell entry in the oocyte cytoplasm and prior to the first cleavage, include: the completion of the meiosis, the exclusion of the second polar body, the pronuclei formation, the replication of the male and female DNA and the chromosome segregation on the newly formed mitotic spindle.

If any of these events is aberrant, one or both of the two daughter cells and their descendants may carry chromosomal anomalies. In other words an uneven first cleavage in size or in content is associated with chromosomal abnormality and aneuploidy.

In vivo all these events occur in a natural environment where the presence of specific molecules and of a dynamic and physiological environment might be an advantage over in vitro culture conditions to ensure optimal cellular functions.

Preliminary data from the pilot study have shown a higher proportion of euploid embryos for sibling oocytes cultured in vivo vs. in vitro. Moreover, in animal models, in vivo cultured embryos have been described with significant reduction of aneuploidies and with differences in the gene expression levels patterns when compared to in vitro cultured embryos. There is also growing evidence that the culture conditions of human pre-implantation embryos can affect the gene expression regulation with measurable effects on embryos and on newborn children.