A Guide to Genetic Testing in IVF: PGT, PGD, and PGS Explained

Assisted Reproductive Technology is the greatest ray of home in the lives of aspiring parents. There have been astounding technological advancements in the past few years that have helped thousands of infertile couples fulfill their dream of becoming parents. Preimplantation Genetic Screening, Preimplantation Genetic Testing, and Preimplantation Genetic Diagnosis are some of the most reliable advanced options.

However, it is important to have complete awareness before opting for any of these technologies and that’s what this blog is all about. So, what is genetic testing in IVF and what should you know about it?

Preimplantation Genetic Testing: An Overview

There are different kinds of genetic tests performed by fertility specialists before embryo transfer. PGT or preimplantation genetic testing is one such screening test performed on an embryo that’s created through IVF (in vitro fertilization). Doctors do it to make sure that there aren’t any chromosomal or genetic disorders. PGT can be of the following three types:

PGT-M: Earlier referred to as preimplantation testing, this test is a type of PGT and it can screen for specific genetic defects or genetic abnormalities (that is, single-gene abnormalities)
PGT-A: The earlier name for this screening test was preimplantation genetic screening. PGS screens for any kind of chromosomal abnormalities. During this process, a single cell is taken from the embryo to test its DNA.
PGT-SR: Structural rearrangements of chromosomes can be detected through this test.

Who Undergoes Genetic Testing for IVF

Doctors suggest PGT under the following circumstances:

Both partners/ just one has a family history of genetic disorders
The man/ woman/ both is a carrier of some kind of chromosomal abnormality
The pregnant woman has reached an advanced age
The mother has suffered recurrent miscarriages in the past

Reasons to Rethink PGS or PGD

Although the various types of genetic testing are becoming increasingly popular in many fertility clinics, there are some compelling reasons why you should think carefully before you decide to screen embryos.

1. Genes and chromosomes are different

PGT does not reduce the risk of miscarriages. Even for embryos that are chromosomally normal a miscarriage can happen because of genetic defects, and this is not something that PGT can predict. So, if you are doing this screening test for embryo selection because you think that you will not have a miscarriage after it, then you should reconsider it.

2. Mosaicism

Not every cell in an embryo is genetically identical, and this phenomenon is termed mosaicism. This means that the 2-3 sells that go for Biopsy may fail to represent the other hundred cells present in the embryo. So, if there isn’t an abnormality in the biopsied cells, a healthy embryo might get detected only because the test results were misleading.

3. Self-correction of embryos

Self-correction is one of the qualities of embryos as they are dynamic entities. Even if some cells turn out to be abnormal, if the remaining cells are normal, they can multiply, resulting in a healthy baby. But if an embryo is discarded based on a false positive result, a viable pregnancy will be lost.

4. Technical challenges

We must not forget the technical complexity of tests like PGS. Most fertility treatment centers do not perform the tests on their own but depend on genetic labs where the biopsy cells are sent. The embryo biopsy results are often confusing and ambiguous, and they may not identify the problems. If the embryologist is not skilled enough, the result can’t be completely trusted. If a biopsy is poorly executed, it can kill or damage a healthy embryo.

5. Psychological impact

Saying yes to fertility treatments like IVF treatment is a big step for any couple. Feeling low at times is common and genetic analysis may add to their anxiety. For a pregnancy to be successful, the emotional well-being of the mother is of utmost significance.

6. Additional expense

Whether you do PGT or not, you will still have to undergo prenatal diagnosis if you get pregnant. It is done to prevent delivering a child with chromosome defects. It takes place at around eight weeks, and it is more reliable. So, if it is compulsory to do PND, why spend extra money on PGT?

Read to Know: double marker blood test in pregnancy

Parting Thoughts

So, PGT, PGD, and PGS in IVF are beneficial in specific scenarios. However, the PGT process is not mandatory to have a rewarding IVF cycle and a successful pregnancy. Moreover, infertility issues differ from one couple to another, and hence, having a personalized preimplantation genetic diagnosis is the best way to achieve pregnancy. Reconsidering using the newest technologies and relying on proven methods will help you get the desired outcome.

If you have more questions regarding IVF or want to further expand your knowledge on PGT testing, get in touch with an accomplished fertility expert or a genetic counselor.

Dr Ritu Agarwal

Dr. Ritu Agarwal is an appreciated IVF expert in Jaipur for IVF therapy, owing to her more than ten years of experience in this field. She is the top IVF specialist in Jaipur who makes every attempt to provide correct counseling and emotional support to patients in order to help them find the ideal solution for becoming parents.

Understanding Genetic Testing in IVF: PGT, PGD, and PGS Explained