More Evidence That Genetic Abnormalities Explain Age Related Infertility!
A recent study adds further evidence to the growing body of evidence pointing to genetic abnormalities as the explanation for age related infertility. This study set out to answer a basic question, “If we evaluate each embryo by a sensitive and highly accurate method, then only transfer embryos that have been proven to be genetically normal, would the effect of advancing maternal age on fertility potential be removed?” The conclusion of a multicenter study recently published in Fertility and Sterility was that implantation and pregnancy rates were not significantly different between reproductively younger and older patients up to 42 years of age when only genetically normal embryos were transferred. The authors point out that as women age, it becomes increasingly difficult to obtain genetically normal embryos, a very important finding in this study.
Analysis of the oldest patients studied (greater than 42 years of age), revealed that in 34 out of 54 cycles, no genetically normal embryos were available for transfer. These patients endured the expense and rigors of a controlled ovarian stimulation for IVF, followed by egg retrieval, embryo biopsy, and PGD with ultimately no possibility for pregnancy in that treatment cycle. When these older patients as well as those in the same age bracket who did have embryos available for transfer are considered as a group, the ongoing pregnancy rate per biopsied cycle was 9.7%. It is very important for older patients who might proceed with this treatment approach be aware as they begin their treatment cycle that the prospect for an ongoing pregnancy in spite of the available technology is just 10%.
This study does provide evidence that older women are capable of producing genetically normal embryos albeit with significantly lower frequency than younger women. When these embryos are transferred, excellent pregnancy rates are achieved.
This study also looked at results when embryo biopsies were done on the 3rd day of embryonic life vs. the 5th day, and found that ongoing pregnancy rates were better in all age groups when biopsies were done on day 5. Several other investigators have reached similar conclusions and day 5 embryo biopsies will likely be the preferred approach in the future. When embryos are biopsied on day 5, most centers will freeze all embryos and transfer only genetically normal embryos in a future cycle. At present, the reason for freezing these embryos is that genetics results are usually not available until the following day (day 6 of embryonic life), and experience thus far has favored transferring embryos on the 5th day. Data is accumulating which should help to answer the question of whether it is best to transfer biopsied embryos on day 6 in the fresh cycle, or freeze all blastocysts and transfer the genetically normal embryos in a future non-stimulated cycle. It is important to note that the pregnancy loss rate was just 7.7% in this study and was not associated with patient age.
Source: “Diminished effect of maternal age on implantation after preimplantation genetic diagnosis with array comparative genomic hybridization,” Fertilityand Sterility, December 2013.