CGH Testing in IVF: Does Age Matter?

CGH embryo testing, by accessing all the cell’s chromosomes, accurately diagnoses aneuploidy (an irregular chromosome component), which is the overriding cause of Reproductive Failure). In most cases, it is the egg, rather than the sperm that determines the chromosomal integrity of the embryo. Since the incidence of egg aneuploidy (and therefore also embryo aneuploidy) increases rapidly after age 35 years, the advisability of doing CGH embryo selection for IVF is in large part tied to the age of the egg provider.

The ideal candidate for CGH-embryo selection is an embryo recipient who ends up with numerous (>6) healthy, day-3 (6-9 cell) embryos resulting from fertilization of a younger woman's eggs (whether her own or donor-derived). The microscopic examination (grading) of embryos cannot accurately determine their ability to make a healthy baby (what we refer to as their "competence"). CGH testing can make this determination much more reliably.

CGH embryo testing is also helpful in younger women, when it is necessary to diagnose the cause of repeated miscarriage, failed IVF, or completely unexplained infertility. In such cases, the embryo is often at the root of the problem (due primarily to egg aneuploidy). Here, embryo CGH can help distinguish between embryo "incompetence" and an implantation problem.

At age 33, about two in five of a woman’s embryos are likely to be "competent"; at 40, about one in six or eight, and at 45 years of age, only about one in every 15-20 eggs/embryos is likely to be CGH normal. This helps explain declining IVF success rates, increasing miscarriages and chromosomal birth defects with advancing age. Thus, the older the woman, the greater the likelihood that CGH testing will reveal that none of her embryos are chromosomally normal.

High aneuploidy rates in women over 39 years of age are the predominant reason we very rarely see triplets or greater (high-order multiples) occurring when these women conceive through IVF using their own eggs. Thus, we can safely transfer more embryos at a time to older women, leaving it up to nature to cull out the defective ones. These higher aneuploidy rates are also the reason that prenatal genetic testing should be done in pregnancies where the woman is in this age group.

Thus, there is a declining need for doing CGH-embryo selection with advancing age of the egg provider. There are, however, a few notable exceptions:

1. The few women over 40 who are high responders and end up with a large number of embryos.
2. Women who wish to bank ("stockpile") their embryos for later use. In such cases we would sequentially perform several stimulation/egg retrieval cycles, without transferring the embryos to the uterus. Instead, we would do CGH and then freeze/bank and store all genetically "competent" blastocysts for future dispensation.
3. When a severe anatomical or immunologic implantation issue is suspected. In such cases it is often a good idea to defer surgery or intensive immunotherapy until "competent" blastocysts are available.
4. When the patient elects to do everything possible to optimize the chance of success for every embryo transferred, and/or to minimize the risk of miscarriage and birth defects.

Always bear in mind that CGH testing identifies "competent" embryos. It does not help produce them or improve embryo quality. As a result, it is the birth rate per embryo transferred (and the quality of life after conception) that is vastly improved...not the success rate per egg retrieval performed.