What is PGT, or preimplantation genetic testing

Last Updated: March 21, 2023

What is PGT?

There’s a ton of scientific stuff that goes on when you opt for an IVF. We are here to break it down into simpler words. Before your embryos are transferred to your uterus, they have their chromosomes checked for abnormalities by using a technique called preimplantation genetic testing or PGT test. One or more cells from each embryo are taken for genetic testing. Only the embryos that are genetically sound are transferred to your uterus, where they bind to the lining.

And that’s how you create a little human!

Now, What Kinds of Genetic Tests are Available?

A disease-carrying gene can be examined in genetic tests in a PGT testing with the embryos. Additionally, it will indicate whether the embryo is disease-free even if it carries the disease. An unaffected carrier is someone who can spread the disease to their children but does not personally exhibit any symptoms.

Another type of genetic test that can look at the chromosomes is the karyotype test which uses amniocentesis or chorionic villus sampling. This test determines whether the fetus has more or fewer than the usual 46 chromosomes. Disorders like Down syndrome (Trisomy 21) and Trisomy 13 can be caused by having too many or too few chromosomes. Translocations, or out-of-order chromosomes, can impede growth or function, and this test can also look for them.

What Exactly is PGS or Preimplantation Genetic Screening?

An embryo undergoes chromosomal abnormality testing as part of PGS. Numerous embryos with chromosomal abnormalities will either not come to term or end up in a miscarriage. Some of a man’s sperm or a woman’s eggs will have chromosomal abnormalities. Numerous factors, including the parent’s age and health history, can influence the percentage of abnormal embryos.

How are Genetic Tests Carried Out?

During an embryo’s growth in the IVF laboratory, one or more cells are taken from the embryo and sent for genetic testing. Various methods are used at various stages of the testing such as

Microarray
Single-nucleotide polymorphism (SNP)
Fluorescent in situ hybridization (FISH)

To improve accuracy, make them easier to use, and provide more information, techniques are constantly evolving and changing. More frequently, genetic testing is carried out using the more recent methods of genome sequencing and microarray.

Who Should Undergo a PGD or PGS Testing?

PGD is for people who have a known genetic disorder or are carriers of one. People who

have had multiple failed fertility treatments
are older
have ovaries that don’t work as expected
have had multiple miscarriages

may benefit from PGS. PGS can also be done for personal reasons by some couples. Anyone with any interest at all in PGD or PGS ought to talk with a fertility expert so the method and any options can be examined.

A Final Word on PGT Testing

PGT testing is an important diagnostic tool to prevent the transmission of any known genetic disorder. Additionally, it aids populations at high risk of bearing certain genetic aberrations in their offspring. A PGT test aids in the prevention of the birth of a syndromic child in cases of advanced maternal age and lessens the trauma of multiple unsuccessful IVF cycles and early miscarriages.

The child is shielded from inherited monogenic disorders by PGT-M. PGT-M, which is based on the idea of a savior sibling, can be used to treat some hematological disorders in children. To provide patients with the best outcomes, PGT technology ought to be incorporated into ART. However, prudent use of this technology and awareness of its drawbacks are essential.

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Preimplantation Genetic Testing - FAQs

1. What does preimplantation genetic testing do?

A screening test known as preimplantation genetic testing (PGT) can be used to genetically analyze embryos created through in vitro fertilization (IVF) prior to transfer.

2. Is PGT-a testing worth it?

The benefits of PGT-A are abundant for patients with a lot of embryos. By removing the embryos most likely to result in a miscarriage, the number of IVF cycles required for a successful pregnancy can be reduced. Like a miscarriage, each IVF cycle is costly and physically and emotionally demanding.

3. What are the risks of preimplantation genetic testing?

PGT testing has not been linked to any health issues. During the procedure of taking a biopsy, there is a small chance that the embryo will get hurt. There is also the possibility of not getting a diagnosis from the biopsy. The inability to test embryos poses the greatest danger to PGT.

4. How accurate is preimplantation genetic testing?

There will be variations in PGD accuracy, and the testing may not be 100% reliable or conclusive. However, for the majority of couples, testing is 98-99% accurate.

5. What is the cost of PGT?

PGS/PGT-A can cost anywhere from $4,000 to $10,000, depending on the fertility clinic and the number of embryos being tested.

6. Is PGT mandatory for IVF?

PGT testing can be performed independently of an IVF cycle, even though it is typically performed in conjunction with IVF. Talk to a doctor if you and your partner are concerned about chromosomal abnormalities or the possibility of having a child with a genetic disease.

7. Why is PGT testing so expensive?

Because it is still a relatively new technology and is frequently not covered by insurance, genetic testing of embryos can be quite costly for patients. The genetics lab you use, the fertility clinic where you are performing IVF, and the number of embryos you are testing all influence how much PGT costs.

8. What is the miscarriage rate after PGT?

The chance of miscarrying is anywhere from 7% to 10% with PGT. This is lower than the 10 to 25 percent miscarriage rate for naturally occurring pregnancies.

9. Who is PGT suitable for?

PGT-M is a good option when a person has a genetic condition that could be passed on to their children, if they are carriers of an X-linked condition, or if they and/or their donor or partner are carriers of the same autosomal recessive condition.

10. Does PGT testing increase the chance of twins?

Medical research data show that, in comparison to ICSI cycles, PGT cycles remain a significant factor associated with an increased risk of monozygotic splitting even after potential confounders are taken into account.

Sources:

1. Monozygotic twinning following embryo biopsy at the blastocyst stage – PMC

2. Preimplantation Genetic Testing (PGT) | RSC San Francisco Bay Area

3. Preimplantation Genetic Diagnosis: how does it work?

4. Preimplantation Genetic Testing: Its Evolution, Where Are We Today? – PMC

On behalf of the editorial team at Parenthoodbliss, we follow strict reporting guidelines and only use credible sources, along with peer-reviewed studies, academic research institutions, and highly respected health organizations. To learn about how we maintain content accurate and up-to-date by reading our medical review and editorial policy.

Harsha Shankar

Harsha has been in the professional content writing space for a little over an year. She is an engineering graduate whose shift into the creative writing genre launched her into unending opportunities that she could only dream about. She identifies as a bibliophile and runs under the influence of mystic, dystopian worlds. She spends most of her time being a novice painter, watching nature's untold stories, and writing verses on her little secret notepad.

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