Preimplantation Genetic Diagnosis Pros and Cons


Preimplantation Genetic Diagnosis [PGD] is the term given to the process of removing a single cell from an embryo during the IVF process so that it can be genetically tested before implantation in the uterus. It isn’t a generic test for all conditions, but will provide information about specific genetic conditions that could affect the embryo as it develops into a fetus. Things like cystic fibrosis can be determined by this testing process. There are some advantages and disadvantages to consider with this testing process, so here are the pros and cons to think about.

What Are the Pros of PGD?

1. It can help to prevent genetic disorders.
When an embryo is in the development stage, it is essentially just a bundle of cells that are still trying to come together to form what will become a human child. At this stage, the genetics of those cells can be tested to determine if there are disorders or diseases that a child created from those cells will face. This will allow a mother or a couple to decide if implanting an embryo is a viable decision to make.

2. It allows older women to still have viable children.
A majority of PGD testing occurs for women who are approaching menopause, but still want to have a child. As a woman ages, the chances of having chromosomally abnormal cells develop increases as well. As women approach the age of 42, the chances increase by 80%. The PGD process can help to screen out embryos that may not be viable.

3. It could detect inherited genetic diseases.
When parents know they are a carrier for a genetic disease, the PGD testing can help to determine if the embryo created was the 1 in 4 or 1 in 2 chance that the disorder was passed from the parent down to the child. Although an uncommon situation, this can help to prevent some very terrible genetic diseases from continuing along the human reproductive chain.

What Are the Cons of PGD?

1. It may traumatize the embryo.
For embryos that are just 3 days old, the PGD biopsy process may weaken the embryo and ultimately make it not become viable for implantation. Research has shown that biopsies that are performed on the fifth or sixth day are much more successful, but that requires waiting times that are not always feasible.

2. There is a learning curve to the process.
Because PGD is a relatively new medical skill, there are going to be some technicians who are incredibly proficient at the biopsy process and some that could use a little more practice. The same could be said for the genetic labs that would be performing the testing on the biopsy as well. The end results could wind up being varied from the same sample because of these inconsistencies.

3. Mosaicism could present a major problem.
When there are two or more different chromosomal patterns in a cell, then the PGD process becomes inconsistent. Research has also shown that certain abnormalities that are initially seen at the embryo stage can self-repair as the cells begin to turn into a fetus. This means that the results may not be 100% reliable.

There are many decisions that need to be weighed by individuals or couples who are seeking help with their fertility. By weighing the pros and cons of preimplantation genetic diagnosis and testing, the best decision to proceed with a potential pregnancy can be made.