A test that checks for raised levels of mitochondrial DNA appears to bolster pregnancy rates at US fertility clinics that offer it, the Guardian reports.
NIHR Oxford Biomedical Research Center researchers who helped develop the test, called MitoGrade, along with Reprogenetics in the US tell the Guardian's Ian Sample that it increases the chances of an IVF pregnancy by some 10 percentage points — a 35-year-old woman would then have a success rate of about 75 percent.
Sample notes that chromosomal abnormalities are behind most cases of failed embryos implantation or miscarriage, but that even with pre-implantation genetic screening for such abnormalities, about a third of embryos don't become successful pregnancies.
"Based on our findings we have devised a test whereby a small number of cells, carefully removed from an embryo, can be measured for the amount of mitochondrial DNA present," Reprogenetics' Elpida Fragouli says.
But why mtDNA levels increase in certain embryos is unclear. According to Sample, extra mitochondria could be produced to help fuel defective embryos to survive, though they eventually fail.