Preimplantation genetic testing (PGT) checks embryos created by in vitro fertilization (IVF) for a variety of genetic issues that could result in implantation failure, miscarriage, and birth abnormalities in the offspring. These genetic flaws include missing or extra chromosomes in the embryo, single-gene diseases like sickle cell anemia, or gene rearrangements that can result in pregnancy loss and birth abnormalities, such as Down syndrome. You can visit https://ifg-ivf.com/ivf-amp-egg-donation/preimplantation-genetic-screening-pgs/ for getting more clarity.
Methods For Preimplantation Genetic Testing:
The three distinct methods of preimplantation genetic testing that can be carried out on embryos during IVF are as follows:
- For an aberrant chromosome number, preimplantation genetic screening is performed. It is a test that examines embryonic cells to see if the number of chromosomes is within the normal range. For example, an embryo can have too few or too many chromosomes if sperm or egg cells divide unequally.
- Genetic testing before implantation for monogenic (individual) diseases. It examines a sample for known gene mutations that one (or both) of the parents carries. The likelihood that a child may be born with a genetic mutation might be increased by a family history of genetic illnesses in either one or both parents.
- Preimplantation genetic testing structural rearrangement is used to check for known chromosomal errors, including inversion and translocation. Patients with known chromosomal structural rearrangements, such as an inversion or translocation, have their embryos tested using this test. In this case, patients with known structural rearrangements are more likely to produce embryos with insufficient chromosomes. A live birth is less likely to occur from damaged embryos. Patients with these issues frequently experience recurrent miscarriages.
Why Are These Tests Performed?
Fertility specialists perform these tests for two key reasons. One is to check for genetic abnormalities in embryos, frequently resulting in failure implantation and miscarriage, leading to unsuccessful IVF. The second is to find embryos that have genetic flaws that could cause a child to inherit diseases like muscular dystrophy or fatal genetic disorders.
Further, such defects prevent embryos from being implanted in the mother’s womb to become pregnant. Genetic mistakes in embryos significantly contribute to unsuccessful pregnancies and live births. Couples interested in PGT testing should speak with a fertility professional to learn more about the different procedures.
How Are These Performed?
All three types involve two fundamental processes: an embryo biopsy and a laboratory analyzing the biopsy to do DNA genetic testing. The biopsy is taken at the blastocyst stage of development for both types of testing. The inner cell mass (ICM), which later gives rise to the infant, and trophectoderm (TE), which enables the placenta to form, comprise the blastocyst.
The biopsy involves the removal of 3–10 cells from the trophectoderm (pre-placenta) for genetic disease testing in the lab. Hence, no disruption of the cells will create the baby. Then, a cycle later, the blastocyst is thawed and transferred to the lady after being frozen immediately after being biopsied to await test results.