In IVF, choosing a good embryo to prepare for embryo transfer plays a very crucial role, particularly in cases where there are many embryos. If the embryo is in good form, the doctor and the couple will expect the embryo to have good growth potential.

IVF is a treatment that aids in the conception of a child and a method to treat infertility or genetic abnormalities. Although IVF is the most effective method of assisted reproductive technology, the chances of having children are still dependent on many factors. There is a chance that it will fail due to chromosomal defects in the embryos, such as extra or missing chromosomal DNA.

During IVF, eggs are collected and fertilized in a laboratory setting. The resulting embryos are then transferred into the uterus for implantation. If you are pursuing or considering IVF, you have likely heard that genetic testing can help increase the likelihood of a healthy pregnancy.

What is PGT?

Preimplantation genetic testing is used to identify chromosomal or genetic defects in embryos prior to an in-vitro fertilization (IVF) cycle. Genetic defects are a primary cause of both failure of an embryo to implant and also subsequent miscarriage after successful implantation.

Types of PGT

1. Preimplantation Testing for Aneuploidies (PGT-A)
2. Preimplantation Testing for Monogenic Diseases (PGT-M)

How does it work?

PGT-A checks for chromosomal normality, meaning the sample cells contain 46 chromosomes (23 pairs). Embryos with missing chromosomes or an extra chromosome are less likely to result in a successful, healthy pregnancy. PGT-M checks the embryos for genetic mutations that cause disorders like sickle cell disease.

How is PGT performed?

IVF is necessary in order to obtain embryos for PGT. After eggs are retrieved and fertilized in the lab, the embryologist will perform assisted hatching on the embryos to help get cells for testing. When the embryo hits the blastocyst stage, some of the cells on the outside of the embryo are biopsied and sent for genetic analysis. The genetic lab then uses a series of procedures to take out the DNA materials from the cells and test them for the genetic disorders.

Who is a good candidate for PGT?

• Women over age 35 (due to higher risk of abnormal embryo genetics)
• Couples who are at a risk of having a child affected with an inherited genetic disease
• History of recurrent miscarriages due to chromosomal abnormalities
• Couples with repeated failures of IVF
• Couples who want to balance the genders in their family

Benefits of PGT

1. Chromosomal abnormalities are responsible for 50% (and perhaps more) of miscarriages in the first trimester. PGT-A or PGT-M identifies embryos without these abnormalities so we can use them for your IVF, thus increasing the likelihood that you’ll have a healthy pregnancy and baby.
2. The procedure may increase the chance of a healthy pregnancy regardless of your age.
3. Sex selection:  It allows patients to choose the gender of their children if they want.
4. Because PGT helps achieve higher pregnancy rates per transfer, you’re less likely to need as many cycles of IVF, which means less time, stress, and cost.
5. PGT can also help you achieve pregnancy with a single-embryo transfer, because of the confidence in the health of that embryo. This lowers the health risks and pregnancy complications that are associated with carrying multiples. These complications may include preterm birth, preeclampsia, and abnormal placental function.
6. PGT procedure is performed before implantation. Couples may feel more comfortable about deciding against going ahead with the pregnancy, if results are not favourable.
7. The procedure helps couples who may be at risk of passing genetic conditions on to their children the opportunity to lower the risk.

At Cell Genomics, we are passionate about understanding, educating, and supporting our patients throughout their journey.

If you have any further questions regarding embryo testing, please do not hesitate to contact one of our specialists, who will be pleased to answer your questions.