Preimplantation Genetic Testing: Types, Pros & Cons
In an IVF treatment, eggs and sperm are fertilized outside the body in a special lab. The fertilized eggs are then cultured for a few days to create an embryo, which is implanted into the woman’s uterus. But do those implanted embryos ensure a better chance of pregnancy and a healthy child?-No, the embryo may have abnormalities and genetic disorders leading to unsuccessful IVF pregnancy. Thus, PGT testing is essential to identify embryo conditions.
This blog post will cover everything you need about PGT, including its types, procedures, benefits, limitations, and ethical considerations.
What is Preimplantation Genetic Testing?
Preimplantation Genetic Testing (PGT) is an embryo test in IVF treatment to select the healthiest embryo before implanting it in the uterus. The test identifies whether the embryo has genetic conditions, chromosomal abnormalities, or inherited disease to ensure that only healthy embryos are transferred. PGT enhances the success rate of IVF, leading to a healthy pregnancy and reduces the risk of miscarriage.
Types of Preimplantation Genetic Testing
The three main types of preimplantation genetic testing are PGT-A (Preimplantation Genetic Testing for Aneuploidy), PGT-M (Preimplantation Genetic Testing for Monogenic Disorders), and PGT-SR (Preimplantation Genetic Testing for Structural Rearrangements).
PGT-A (Preimplantation Genetic Testing for Aneuploidy)
PGT-A identifies chromosomal abnormalities, such as extra or missing chromosomes, which can lead to conditions such as Down syndrome (trisomy 21) or Turner syndrome. It helps select embryos with the correct number of chromosomes, improving the chances of a successful IVF pregnancy.
PGT-M (Preimplantation Genetic Testing for Monogenic Disorders)
PGT-M screens embryos for specific single-gene disorders (monogenic disorders). It is beneficial for couples who have genetic conditions such as cystic fibrosis, sickle cell anemia, or Huntington’s disease. PGT-M can prevent the inheritance of known genetic diseases, allowing couples to have children free from specific genetic disorders.
PGT-SR (Preimplantation Genetic Testing for Structural Rearrangements)
PGT-SR detects structural chromosomal rearrangements, such as translocations or inversions, that can lead to reproductive issues, including recurrent miscarriages or congenital disabilities. Couples who have a history of recurrent miscarriages or are known to carry balanced translocations can benefit from PGT-SR to increase the chances of having a healthy pregnancy.
How Does Preimplantation Genetic Testing Work?
In an IVF process, when embryos are developed enough for testing, they undergo genetic testing ((PGT-A, PGT-M, or PGT-SR). After the test, the embryos’ DNA is analyzed to identify chromosomal abnormalities, gene mutations, or structural rearrangements. Based on genetic testing, the healthy embryo is transferred.
Ovarian Stimulation, Egg Retrieval, and Fertilization
The first step in the IVF process is ovarian stimulation, where the woman undergoes hormonal treatment to stimulate the ovaries to produce multiple eggs. These eggs are then retrieved in a minor surgical procedure and fertilized to create embryos.Embryo Culture
The embryos are cultured for a few days, typically 5 to 7 days, until they reach the blastocyst stage, when they have developed enough to be tested.Embryo Biopsy
A small number of cells (usually 5 to 10) are removed from the embryo for genetic analysis. This biopsy is performed at the blastocyst stage, as the embryo is sufficiently developed to allow for accurate testing.Genetic Testing
The extracted cells are sent to a laboratory, where they undergo genetic testing (PGT-A, PGT-M, or PGT-SR, depending on the reason for the test). The laboratory analyzes the embryos’ DNA to identify chromosomal abnormalities, gene mutations, or structural rearrangements.Embryo Selection
Based on the genetic testing results, the healthiest embryos are selected for implantation, while those with significant abnormalities are discarded. The selected embryo(s) are then transferred into the woman’s uterus for potential pregnancy.
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Get StartedBenefits of Preimplantation Genetic Testing
Preimplantation Genetic screening helps to increase healthy pregnancy, reduce miscarriage risk, and enhance overall IVF success rate.
- Increased Chance of a Healthy Pregnancy: Genetic screening helps to identify genetic disorders and chromosomal abnormalities in embryos that could result in miscarriage and birth defects. Selecting embryos with the highest chance of leading to a healthy pregnancy increases the likelihood of a successful IVF outcome.
- Reduced Risk of Miscarriage: Couples who experience recurrent miscarriages due to genetic or chromosomal abnormalities can benefit from PGT. By ensuring the embryos are genetically normal, PGT reduces the chances of early pregnancy loss.
- Improved IVF Success Rates: Identifying embryos with genetic abnormalities and selecting healthy embryos increases the success rate of IVF. This test is particularly beneficial for older women with a higher risk of chromosomal abnormalities in their eggs.
- Avoiding Genetic Diseases: PGT-M allows couples who are carriers of genetic disorders to avoid passing those diseases on to their children, ensuring a healthy baby and reducing the emotional and financial burden of managing a genetic condition.
Limitations of Preimplantation Genetic Testing
Not 100% Accurate: False positives and negatives can occur, leading to incorrect conclusions about the embryo’s genetic health. Further testing may be needed to confirm the results.
Limited to Certain Genetic Conditions: PGT may not detect all possible genetic conditions, especially those that are less common or outside the scope of the test.PGT is primarily used to test for genetic disorders, chromosomal abnormalities, and structural rearrangements.
- Emotional and Financial Costs: IVF and genetic testing can be expensive, and multiple cycles may be needed to achieve a successful pregnancy. The process can be emotionally taxing for couples who face challenges during the IVF journey.
- Not Available Everywhere: Not all IVF clinics offer PGT, and the availability of genetic testing may depend on your location, the clinic’s resources, and the specific conditions being tested.
Conclusion
Preimplantation Genetic Testing (PGT) enhances the IVF process by allowing couples to select the healthiest embryos, reducing the risk of genetic diseases and chromosomal abnormalities. This technology significantly boosts IVF success rates, increases the chances of a healthy pregnancy, and offers peace of mind to families.
Sishu Fertility Clinic, one of the top IVF centers in Nepal, can help couples maximize your chances of a successful and healthy pregnancy. Start your IVF journey with the Sishu family for a positive IVF outcome.
Frequently Asked Questions
IS Preimplantation Genetic Testing(PGT) available in Nepal?
Yes, PGT or DNA tests are available in many IVF centers in Nepal. Many IVF clinics in Kathmandu and Chitwan offer genetic screening.
What is the cost of Preimplantation Genetic Testing(PGT) in Nepal?
PGT costs between Rs. 25,000 and Rs. 30,000, depending on the clinic. If you choose IVF treatment, the cost of PGT is included in the package, so you don’t need to pay extra for the test.
Sishu Fertility Clinic & IVF Center is a leading provider of fertility and IVF treatments in Nepal, known for its high success rates and expert care. With a team of top fertility specialists and gynecologists, the clinic offers personalized treatments, including IVF, IUI, ICSI, PCOS and advanced reproductive technologies, ensuring optimal outcomes and compassionate support throughout the fertility journey.