Researchers from the Research Center of the University of Montreal Hospital (CRCHUM) suggest that in the future it will be possible to improve the quality of the eggs of older women by intervening on the cell cycle level. They found in mouse oocytes that some chromosomes move more slowly during meiosis, the crucial phase of cell division, and the lag contributes to the uneven distribution of chromosomes and the formation of cells with an abnormal number of chromosomes. This abnormality, called aneuploidy, is one of the leading causes of infertility and explains, in part, why older women are unable to conceive and carry a pregnancy to term. In order to give the slowest chromosomes time to reach their destination, the researchers artificially extended meiosis with a chemical. Using high-definition imaging techniques, the researchers found that this slowdown before cell division limits aneuploidy. In the future, this research could be used to improve the efficiency of eggs used during IVF.