An embryo screening test could significantly increase IVF success rates, US researchers have found. The test allows doctors to quickly select the most likely embryos for successful implantation into the womb, helping reduce the risks of genetic birth defects, miscarriage and failed pregnancy.
Researchers compared screened with non-screened embryos and found 87 percent of patients who underwent screening had a healthy baby. This fell to 68 percent for patients whose embryos were transferred without the test. 'In this particular test we can get an answer in four hours, we do not have to cryopreserve (freeze) the embryos and we can implant them the next day', explained study leader Dr Richard Scott, a specialist in 24-chromosome aneuploidy screening.
During the test, a biopsy is taken from a five-day old embryo to examine whether it has two copies of all 23 chromosomes. Almost half the embryos resulting from IVF are aneuploid, meaning they have too many or too few chromosomes. Implantation of such embryos could lead to the development of various genetic conditions or spontaneous abortion. Only those with the exact set of 46 chromosomes are selected for use in IVF after the test.
Presenting his research at the American Society for Reproductive Medicine (ASRM), Dr Scott also explained how the improved success rate also meant only one embryo needed to be transferred at a time, reducing the risk to mother and baby from a multiple pregnancy.
Currently genetic screening is available in the UK to test for inherited diseases including cystic fibrosis and muscular dystrophy, but some fertility doctors believe such tests should be routinely offered. The study involved 80 patients of an average age of 34 and the researchers now propose to continue with a three-month trial involving up to 500 patients.
It is thought the screening test will cost an additional £1,000 to £2,000 in addition to standard IVF costs. Tony Rutherford, chair of the British Fertility Society, expects the test will take two to three years to develop.