IVF is a technique of Assisted Reproductive Technology (ART) used to cure infertility and finally helps in conceiving. The IVF process involves ovarian stimulation to enhance egg production, egg and sperm retrieval, fertilizing egg using sperms to create an embryo in the lab and finally transferring the embryo to the intended mother’s uterus.
Prior to the embryo transfer to the uterus, Preimplantation Genetic Test (PGT) is done to test embryos for a genetic disorder that may lead to miscarriage or birth defect. Dr Shivani Sachdev Gour – an IVF specialist doctor in Delhi explains the genetic testing in detail.
Classification of Preimplantation Genetic Testing
Based on the use cases, PGT is divided into two categories.
- PGS (Preimplantation Genetic Screening)
PGS is used to check embryos for any abnormality causing implantation failure. This test helps in preventing miscarriage and ensures IVF success.
- PGT – A: PGT – A is to identify the aneuploidy, a condition of abnormal chromosome number. A person receives equal numbers (23) of the chromosome from each parent that forms 46 chromosomes. If there is an imbalance in embryo cells, it may lead to Monosomy, absence of a chromosome or Trisomy, transfer of an extra chromosome. The contenders for this test are those women who faced past miscarriages, embryo transfer failure, having unexplained fertility, and having age 35 or above.
- PGD (Preimplantation Genetic Diagnosis)
PGD is used to identify the faulty chromosome in the embryo. Embryo, carrying the defect is not implanted to the uterus, thus genetic abnormality is restricted to pass on to the next generation.
- PGT – M: PGT – M is to identify a specific gene mutation that either one or both parents suspect to transmit. The results of this condition are Sickle cell anemia, fibrosis cyst, mutation BRCA1 and BRCA 2, and Huntington’s disease.
- PGT – SR: PGT –SR is to check embryo for chromosome structural rearrangement, either inversion or translocation. This situation affects the chromosome material and leads to Reciprocal translocations and Nonreciprocal translocations.
The procedure of IVF with PGT
PGT is a section of the IVF process. For a successful IVF procedure; contact SCI IVF Hospital – the best infertility clinic in Delhi.
- At first, ovaries are stimulated using hormonal medication for the production of more eggs. During ovulation, eggs are collected. Simultaneously, the sperm sample is also collected
- Then, the egg is mixed in a dish with sperms and the fertilization is done to create an embryo.
- Now, embryos are kept for 4-5 days in an incubator for cell division and further growth.
- Some cells are retrieved from each embryo for PGT testing. Meanwhile, embryos are kept frozen.
- Chromosomes of the cells collected from each embryo are tested for genetic abnormalities.
- One of the embryos having no abnormality is then implanted into the mother’s uterus. The rest embryos with genetic faults are destroyed.
Benefits of PGT
It facilitates the following benefits in the IVF process.
- PGT helps in risk mitigation of miscarriage and inherited genetic abnormalities to pass on.
- PGT can efficiently test lots of genetic conditions in one go.
- It provides an opportunity for aspiring parents to choose whether to move on with the pregnancy or not.