Genetic Testing

What Is Genetic Testing?

Genetic testing plays an important role assisted reproductive techniques (ART), particularly in vitro fertilisation (IVF) as it identifies embryos that are genetically healthy and have a higher likelihood of developing into healthy babies. This advanced testing method helps couples facing fertility challenges improve their chances of achieving a successful pregnancy.

Different Types Of Genetic Testing

PGT (Preimplantation Genetic Testing) is a broad term that encompasses various genetic testing procedures performed on embryos before implantation as part of assisted reproductive technologies (ART). These procedures aim to identify embryos with the correct number of chromosomes (euploid embryos), which have a higher likelihood of developing into healthy babies.

PGT-A (Preimplantation Genetic Testing for Aneuploidies), also formerly known as PGS (Preimplantation Genetic Screening), is one of the most common and advanced forms of PGT. It isa comprehensive technique that analyzes the entire genome of an embryo using advanced technologies like whole-genome sequencing. This allows for a precise assessment of chromosomal abnormalities and helps identify embryos with the correct number of chromosomes (euploid embryos).

PGT-D (Preimplantation Genetic Diagnosis) is used to detect specific genetic disorders in embryos. It analyses the DNA for known mutations associated with those conditions, allowing couples to select embryos that are unaffected by the disorder. For example, PGT-D can be used to select embryos that do not carry the mutation for cystic fibrosis or sickle cell anemia.

Both genetic testing methods can be used alongside traditional IVF and egg donation cycles. The most appropriate testing approach can vary depending on the patient and their individual circumstances.

What Is The Genetic Testing Process?

The genetic testing process for IVF involves a series of steps designed to identify embryos with the highest likelihood of developing into healthy babies.

• Embryogenesis: IVF begins with the retrieval of eggs from the woman’s ovaries. These eggs are then fertilized with sperm in the laboratory, resulting in embryos.
• Blastocyst Stage: The embryos are allowed to develop in the laboratory for about five days, reaching the blastocyst stage. This stage is characterized by the formation of an inner cell mass (ICM), which will eventually develop into the baby, and an outer trophectoderm, which will form the placenta.
• Biopsy: A small sample of cells is taken from the ICM of the blastocyst using a specialized needle or pipette. This process is known as embryo biopsy and is typically performed on the day of the fifth day of development.
• Genetic Testing: The biopsy samples are then sent to a laboratory for genetic testing.
• Selection and Transfer: The results of the genetic testing are used to select the embryos with the most favorable genetic makeup. The healthiest embryos are then transferred to the woman’s uterus, with the goal of achieving a successful pregnancy.

When Is PGS Testing Recommended?

Genetic testing is typically recommended for couples who have:

• A history of recurrent miscarriage
• A history of failed IVF cycles
• Known genetic disorder(s)
• Previously had, or are at risk of having aneuploid embryos (embryos with a chromosome imbalance)