Researchers from the UK have developed a new way of testing human eggs for chromosomal abnormalities that doesn’t involve a biopsy of the egg itself. This advancement could help prevent damage to healthy eggs as well as explain why these abnormalities exist in the first place.
When a woman undergoes an IVF treatment the eggs that are removed from her ovaries are tested for chromosomal abnormalities prior to being implanted back into her uterus for pregnancy. These types of abnormalities are responsible for Down’s syndrome, repeat miscarriages, failed IVF and more.
Up until now the standard procedure for this type of testing is to remove a small cell biopsy from the egg or embryo for testing. However, this places the egg at risk for extensive damage making it unsuitable to be re-implanted back into the uterus for pregnancy.
Researchers from the UK have come up with another type of test which they say can accurately test for abnormalities – without damaging the eggs. Dr Elpida Fragouli, a research scientist at the University of Oxford and director of cytogenetics at Reprogenetics UK explains:
In the ovary, human eggs are surrounded by a cloud of tiny cells, known as cumulus cells. The egg and the cumulus cells are in constant communication and depend upon each other for continued viability. We wondered whether the presence of chromosome abnormalities, which are extremely common in human eggs and are incompatible with the formation of healthy embryos, would have an effect on the surrounding cumulus cells. This is important for two reasons. Firstly, an increase in the understanding of how chromosome abnormalities arise in eggs is desperately needed. For several decades we have been aware that chromosome problems are common in human eggs, that they are the major cause of miscarriage, and that they are responsible for conditions such as Down syndrome. Yet the origins of chromosome abnormalities remain poorly understood. A better understanding of the factors that lead to chromosome abnormality may help us think of ways to reduce their frequency.
Secondly, if chromosome abnormalities in the egg result in changes in the surrounding cumulus cells, it is possible that this could lead to a new way of testing eggs, before they are fertilised, revealing those with the correct number of chromosomes as well as those that are abnormal. This could help patients undergoing IVF, by identifying the eggs most likely to make a baby without having to use an invasive and expensive procedure. Cumulus cells are routinely stripped off eggs during IVF treatments and are usually discarded, so it should be straightforward to obtain them for analysis.
Follow-up testing is currently underway and if all goes well the researchers expect that clinical trials for this procedure will begin as early as next year.
For more information about IVF and genetic screening please contact IVF NY experts the Center for Human Reproduction at www.centerforhumanreprod.com
Further reading:IVF failure frequently caused by genetics
