Preimplantation genetic testing (PGT) is an optional test performed on embryos developed during IVF. The results of this test empower you to make an informed decision regarding the likelihood of a genetic defect in your future child, and enables Mark to choose an embryo with the highest chance of resulting in you holding a healthy baby in your arms nine months later.
Once an embryo is formed through the IVF process, a tiny sample is taken via biopsy. This sample consists of several cells from a part of the embryo that will later develop into the placenta – no cells that will grow into your baby are disturbed. These cells can then be analysed in a lab for genetic defects.
Preimplantation genetic testing for aneuploidy assesses the embryo for the correct number of chromosomes. Any number other than 46 (23 pairs) is called aneuploidy, whether it’s too few or too many chromosomes. Examples of conditions resulting from aneuploidy include Down syndrome, Turner syndrome, and Patau syndrome.
Preimplantation genetic testing for a monogenic disease is offered to people who have a known genetic abnormality themselves or in their family. It can also be used as a follow-up to an abnormal genetic carrier screening test. PGT-M assesses the embryo for specific conditions resulting from genetic mutation, including sickle cell anaemia, Huntington’s disease, and cystic fibrosis.
Preimplantation genetic testing for structural arrangements is a test for the presence of balanced translocation or chromosomal inversion. This means the correct number of chromosomes are there, but in a different order. Although a parent-to-be has the correct number of chromosomes, this different arrangement increases the likelihood of an unbalanced number of chromosomes in the embryo. This leads to a higher risk of miscarriage or genetic conditions in the baby.
By identifying genetic abnormalities, we can rule out embryos that may fail the implantation stage, have a high risk of ending in miscarriage, or will develop into a baby affected by a genetic disorder.
If you or your partner have a history of genetic conditions, such as muscular dystrophy, PGT can offer you peace of mind that your future child won’t be affected by the same condition.
PGT is also recommended for women who are experiencing infertility in its various forms, including recurrent pregnancy loss, previous unsuccessful fertility treatments, and those with unexplained infertility. The results of PGT can help to shed light on the underlying causes and improve success rates of future fertility treatments by ensuring only the healthiest embryos are selected for IVF. If your PGT results identify a genetic abnormality, Mark can offer you advice on next steps through Genea’s genetic counselling service.
Transferring a tested embryo which has been found to be chromosomally normal can reduce the risk of miscarriage but does not completely remove the chance of miscarriage. The chance of pregnancy is higher than with an untested embryo but not a guarantee.
It is also important to know that the testing process is 95% accurate therefore there is a 1 in 20 chance of error. Depending on how comfortable you are with this, you may choose to undergo further testing during your pregnancy for genetic conditions in the foetus.
In some cases, the PGT returns a result of mosaicism. Mosaicism is when two different results are obtained from an embryo biopsy, e.g. 50% normal chromosomes and 50% with an extra chromosome. This result is found in about 4% biopsied embryos and some individuals choose not to use these embryos, given concerns that the resulting pregnancy may be abnormal. However, there is still a chance the resulting pregnancy could also be normal.
With advanced training and expertise in genetic testing, Dr Mark Livingstone is available for consultation via telehealth or in-person appointments. Contact us today to get started.
