New results suggest that a new genetic screening test for embryos could significantly improve IVF success rates.
The test from Cambridge-based company Blue Gnome examined chromosomes from IVF embryos using an arrayCGH-based method, 24Sure.
Published in Molecular Cytogenetics, the new screening method was compared with current approaches (visual inspection of embryos) for ‘good prognosis’ women (under 35 with no history of miscarriage) having first-time IVF. Both the initial and ongoing (20 weeks) pregnancy rates were higher for the Blue Gnome approach (70.9% and 69.1%) than for the normal procedures (45.8% and 41.7%).
IVF experts have commended the approach, saying it can boost the number of healthy pregnancies resulting from transfer of single embryos. Single embryo transfer during IVF is preferable to avoid the much higher-risk multiple births, but when success rates are low and treatments are expensive, there is pressure to implant more than one.
Blue Gnome chief executive Nick Haan cautioned that further research was needed, but said the results were exciting because it suggested that: “24-chromosome screening and single-embryo transfer has the potential to become the default standard of care for all IVF cycles worldwide".
Comment: The genetic screening of the embryos appeared to not only significantly improve overall conception rates but also reduce the proportion of early pregnancy losses among the IVF patients, making it a highly promising approach. In theory, it might perform even better among poorer prognosis patients (older women and those with a history of miscarriage) relative to current methods, as chromosomal abnormalities probably underlie a fair proportion of failed IVF and pregnancy loss in these groups. However, more research will be needed to find out.