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Genetic Screening

There are several reproductive health options for genetic screening depending on your medical history, fertility investigation results and treatment procedure. The most common genetic screening includes genetic carrier screening and PGT-A/PGT-M.

Genetic Carrier Screening

Carrier screening is a bloodwork which helps to identify patients who are at increased risk of having a child affected with a genetic disorder, providing actionable information for the next steps of their reproductive journey.

This test is mandatory for patients who are using a known or anonymous donor sperm sample to reduce the chance of reproductive genetic risk and for those that with known genetic disease that impact their reproductive goals.

Once the test results are reviewed and depending on the outcome, genetic counseling and an in-depth discussion of reproductive options will be available to determine the best treatment plan.

Preimplantation Genetic Testing

Preimplantation Genetic Testing (PGT) is a screening test performed on embryos to identify chromosomal abnormalities before they are placed in the uterus for implantation. It is important to note that doing this test does not guarantee an implantation or a live birth. However, this procedure is able to help improve implantation by detecting genetic problems in the embryo and reduce the odds of miscarriage or failed IVF cycle.

There are two types of testing:

This includes testing for trisomies (having an extra chromosome), monosomies (having a missing chromosome) or sex chromosome abnormalities that would lead to a non-viable embryo, failed transfer or miscarriage. An example of this would be Down Syndrome or Turner Syndrome.

This test is appropriate for patients with a known single gene disorder that could be passed on to their children. This helps reducing the risk for a specific genetic condition to occur in their embryos. An example of this would be Cystic Fibrosis or Sickle Cell Anemia.

This test is an option for patients who have a chromosome translocation or inversion who is at risk to produce embryos with missing or extra chromosomes which most likely can result in miscarriages, stillbirth or a child with serious health issues.

PGT starts with the IVF cycle and egg retrieval, where the egg is fertilized with sperm in the embryology lab. After fertilization, the embryo(s) are monitored for 5 or 6 days until they reach a stage called blastocyst. A biopsy is then performed, where a small number of cells are biopsied or removed from each embryo. The embryo will be vitrified (frozen) and stored in the lab and the biopsied cells will be frozen and shipped off to a genetics lab. PGT results are ready about 10 to 15 business days after the biopsy.

Once the results are received and reviewed, only the normal embryo or embryo with no results can be transferred back to the uterus at any time, even as soon as the next cycle. A mosaic embryo can be considered for transfer after genetic counselling.

Is PGT Right For Me?

  • If you wish to screen your embryos in the hopes of having a higher chance of implantation or success prior to embryo transfer
  • If you are above 35 years old as risk for genetic conditions such as down syndrome increases
  • If you have history of recurrent pregnancy losses
  • If you have male factor or male infertility
  • If you had previous unsuccessful IVF cycles
  • If you have a genetic condition increasing the risk of passing them to your future children
  • If you have a child affected by a genetic condition and would like to reduce the chance of having your future children inherit the same genes

Post Pregnancy Genetic Screening

At approximately 11 weeks + 3 days to 13 weeks + 5 days, it is recommended for patients to do an NT ultrasound and an EFTS Bloodwork.

The Nuchal Translucency (NT) ultrasound measures the fluid at the back of the fetal neck,  identifies the nasal bone and can detect structural defects.

The Early First Trimester Screening (EFTs) is a bloodwork.

Both data combined determine if there are any risks for Trisomy 21 (down syndrome), trisomy 13 and 18. Both of these tests are OHIP covered and are done on the same day.

Non Invasive Prenatal Screening (NIPT) is a private pay blood work identifying risks for chromosomal defects Trisomy 21,18,13  and more (not just Down Syndrome) and fetal sex (if requested) as early as  9+ weeks  to 10 weeks.

Patients over 40 years old, twin pregnancy or patients who’s EFTs come back positive can have their NIPT covered by OHIP.

For more information about Prenatal Screening – Read More