PGD is a procedure that occurs on an embryo that analyzes the embryos genetic contents. The goal of this analysis as used with in vitro fertilization is to determine which embryos have defects and which are “healthy.” However, as this expensive procedure (~$3,000) rapidly expands, many questions exist as to how accurate it results really are in detecting chromosomal abnormalities. An article in the Los Angeles Times recently addressed this issue with the specific question of how effective the procedure is with older women undergoing in vitro fertilization. The article states that many in the field are not very confident in the procedure when it is used “on the embryos of otherwise healthy mothers whose only problem is the decline in fertility that inevitably comes with advancing age.”
Surveys have shown that 2/3 of PGD users are using the procedure to detect abnormal chromosomal counts as opposed to detecting genetic diseases. Abnormal chromosomal counts are far more common in older mothers and can lead to miscarriage or birth defects. The problem in this use of PGD is that with older mothers, PGD may not be helpful to finding a healthy embryo because there are no healthy embryos due to fertility issues related to age. A Belgian study found no improvement in full-term pregnancy rates for 150 women 37 and older who had PGD done compared to an equal number of women who did not have the procedure done. In a similar study performed by Scott, a group of women in the age group of 32 to 38 produced similar results.
These results are due to the fact that while PGD may limit the number of miscarriages, the procedure does not increase the number of viable embryos. Also, women having PGD performed will have embryos discarded that “may” be healthy. This means that the procedure may in fact be lowering the number of viable embryos that only appeared to be abnormal. Scott said that 1/3 of abnormal embryos self-correct later in development.
So what does all this mean? It does not mean that PGD should not be used because PGD is a very good option for women seeking to avoid specific genetic abnormalities. However, older women with possible fertility issues should be informed about what is exactly happening with the procedure and how the results may affect an abnormal embryo that only has a 66% of actually being abnormal.
3 comments:
I am pretty amaze to see how those thins related to DNA are about to change the way we live!.
I would bet that this is just the begging of something much bigger than we would have thought.
I can imagine getting viagra online anytime you need it and stuff like that
PGD may be used if one or both of the parents have a known genetic abnormality, as the embryos are put through a panel of tests looking for various common chromosome abnormalities. As a result, only normal embryos are transferred to the uterus for implantation.
PGD Preimplantation Genetic Diagnosis
PGD may be used if one or both of the parents have a known genetic abnormality, as the embryos are put through a panel of tests looking for various common chromosome abnormalities.
PGD
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