Study: Full chromosomal testing significantly increases IVF pregnancy rates
The results of the first randomised study into a form of Preimplantation Genetic Diagnosis (PGD) testing, 24Sure Array CGH (comparative genomic hybridization) technology, has found it significantly increases the pregnancy rates in IVF patients.
Published in May in the Journal of Molecular Cytogenetics, the American study found that 24Sure Array CGH technology delivers a 65% increase in pregnancy rates, even in younger patients with more favourable IVF outcomes.
Dr Leeanda Wilton, Scientific Director, Preimplantation Genetics for Melbourne IVF and IVFAustralia welcomed the study, stating the results mirror our Advanced Embryo Selection successes.
Melbourne IVF introduced Advanced Embryo Selection using 24Sure Array CGH technology in December 2010 and extended the service to sister clinic IVFAustralia Jnue 2011, as it is recognised as the technology of choice worldwide to provide full chromosomal analysis on developing embryos.
“Since Advanced Embryo Selection was introduced, more than 20 babies have been born at Melbourne IVF and 4 at IVFAustralia with another 80 women currently expecting across the two clinics,” Dr Frank Quinn, Clinical Director IVFAustralia.
“We have no doubt that without Advanced Embryo Selection technology, many of these babies would not have otherwise been conceived and born,” he said.
Advanced Embryo Selection, using the 24Sure Array CGH technology, screens all 24 chromosomes in a developing embryo, which is a significant advance on earlier forms of PGD testing that only screened 8 out of 24 chromosomes. A single cell is biopsied (removed) from the embryo on day three of development in the laboratory, and the DNA from the cell’s nucleus is multiplied thousands of times before being placed on a microarray, or DNA chip, where it is compared with normal male and female DNA. This allows the accurate detection of chromosome errors, increasing the chance of a healthy baby resulting from the transfer of a chromosomally normal embryo.
IVFAustralia’s sister clinc Melbourne IVF pioneered earlier forms of full chromosomal testing using single cell CGH from the mid-1990s, and reported the world’s first baby from this technology in 2001.
Dr Wilton, who is also Chair of the European Society of Human Reproduction and Embryology PGD Consortium’s Array Working Group, said the significance of Advanced Embryo Selection is its ability to perform rapid testing on a single cell.
“Using Advanced Embryo Selection, testing can be performed on a single cell from a day 3 embyro, whereas similar forms of technology require embryos to develop to the blastocyst stage on day 5 in order for several cells to be available for testing,” Dr Wilton said.
“About 50% of all embryos fail to reach the blastocyst stage on day 5, and this means a number of patients have no embryos that can be tested. Some of these embryos are viable and can result in live births.
“At Melbourne IVF we have a number of pregnancies from embryos that were biopsied on day 3, were found to be chromosomally normal and went on to a successful pregnancy, yet would not have satisfied the criteria for a day 5 biopsy,” she said.
“Advanced Embryo Selection also provides accurate results within 30 hours, meaning patients can undertake a fresh embryo transfer, and their treatment can continue uninterrupted, whereas in most cases embryos that need to be biopsied on day 5 must be frozen because the results are not available in time to perform a fresh embryo transfer.
“Our scientific team in Preimplantation Genetics is one of the most advanced in the world and we have the expertise and experience necessary to analyse and interpret the results, giving patients the greatest confidence in their treatment outcome,” Dr Wilton said.
Advanced Embryo Selection is most suited to couples or single women where:
- 5 or more embryos have been replaced without success,
- the woman is aged 38 or more
- there is a history of recurrent miscarriage
- there has been a previous pregnancy with a chromosome error e.g. Down syndrome
Study Reference: The Journal of Molecular Cytogenetics by Yang et al 2012, 5:24 (2 May 2012)