Novel genetic test improves pregnancy rates in older women
Washington, June 30 : Scientists from University of Oxford, UK claim to have developed a new less invasive genetic test that has found to greatly improve pregnancy rates in older women with failed attempts.
The new test, developed by Dr. Elpida Fragouli, examining chromosomes in human eggs a few hours after fertilisation can identify those that are capable of forming a healthy baby.
She said that her team''s work had already enabled seven ongoing pregnancies in a group of older women with a history of multiple failed IVF attempts.
"Out of 35 patients who had embryo transfers after the test, we achieved a pregnancy rate of 20pct, which is exceptional considering the extremely poor prognosis of the women involved." she said.
"This represents a doubling of the usual pregnancy rate for women who fall into this category, which is otherwise, at best, under 10pct and, at worst, zero.
"To date, we have two live births from this group, and all the other women who became pregnant have maintained their pregnancies. The study is continuing, and we believe that we will achieve more pregnancies with the help of this technology in the future," she added.
During the study, the scientists used the Comparative Genomic Hybridisation (CGH) technique to count the chromosomes in each egg.
It examines the fertilised eggs by looking at polar bodies, tiny cells that are a by-product of egg development. The chromosomes of polar bodies provide an indication of whether the corresponding egg is normal or abnormal; if the polar bodies have the wrong number of chromosomes, so does the egg.
The scientists studied 400 fertilised eggs generated by women with a very poor reproductive history and with an average age of 42 who were undergoing IVF because of being unable to conceive or to maintain a pregnancy.
They found that more than half of all the eggs produced by these women had chromosomal abnormalities, and therefore the resulting embryos were also chromosomally abnormal.
Some of the women had a tendency to produce eggs that were extremely abnormal and carried multiple chromosome errors.
This, according the scientists, could explain the poor reproductive history of these women.
"But where we could find fertilised eggs free of chromosomal abnormalities, the resulting embryos were also normal and their transfer to the mother led to pregnancies," said Dr. Fragouli.
"Results suggest that the use of this technique will improve IVF success rates for poor prognosis patients. It is also likely to achieve a reduction in congenital abnormalities such as Down''s syndrome, as well as a reduction in the frequency of spontaneous miscarriage," she added.
The findings were presented at 25th annual conference of the European Society of Human Reproduction and Embryology. (ANI)