When we first embarked on our IVF journey in HK, we had no idea what PGS or PGD was (now known as PGT, Pre-implantation Genetic Testing). They were never mentioned by any of our fertility doctors so we didn’t even know about these options. It was only after months of extensive research and speaking to people that I discovered that these genetic tests existed, and the events that followed this discovery were what led to the birth of our two beautiful daughters. I want to highlight that we did our PGT in Thailand because Hong Kong had very, very stringent regulations and policies at the time. You can read more about those here (20.05.2016 (Abortion Pill) but in a nutshell, you need to meet the age of 38, have several miscarriages and IVF attempts under your belt and be approved by a panel of independent doctors. I was 34 at the time and wasn’t going to wait so we are very thankful to have found Thailand as an option.
If you’re about to embark on your IVF journey, I’d highly recommend you ask your doctor about PGT. It will cost a little more but it will be well worth it as IVF alone isn’t guaranteed to work first time (or at all for some). However, added PGT would greatly increase your chance of conceiving a healthy baby (accuracy rates are approx. 84% plus) and could ultimately save you time, heartache and money by being more likely to succeed the first time. Even if your doctor can’t perform it, they can at least give you the lowdown on it and if you decide to pursue PGT, you can find centres that offer it. For those in Asia, I know that Thailand, Taiwan and Australia offer PGT. However, different regulations apply to each country so best to double check these. Good luck!!
Pre-implantation Genetic Testing (PGT)
In recent years, the term PGT has been used to replace the terms PGS (Pre-implantation Screening) and PGD (Pre-implantation Diagnosis). PGT can be broken down into three test categories: PGT-A, PGT-M and PGT-SR.
PGT-A for Aneuploidies
What is it?
PGT-A determines whether an embryo contains the normal number of chromosomes which is 46. Embryos with a normal number of chromosomes are “euploid” and those with an abnormal number are “aneuploid.” The purpose of PGT-A is to avoid transferring an abnormal embryo with issues such as Down Syndrome, Edwards Syndrome, Patau Syndrome and Genotype XXY/X etc into the uterus.
Who can benefit from it?
- Couples with severe male factor infertility, recurrent IVF failures, older than 35, PCOS or very large number of embryos.
- Couples experiencing multiple unexplained miscarriages or who may have different types of translocations where a piece of one chromosome breaks off and attaches to another chromosome resulting in a gain or loss of a cell’s genetic material.
How is it performed?
- An embryo biopsy is performed whereby approx. 3-8 cells are removed from each day 5 embryo (a blastocyst) and the cells are sent to a lab for testing.
- The lab uses technology to count the number of chromosomes within each cell.
- The embryos are then frozen and transferred later if they are normal.
PGT-M for Monogenetic Disorders
What is it?
PGT-M looks for specific markers for certain diseases/genetic disorders that usually run in families for example, thalassemia, cystic fibrosis and sickle cell anaemia. PGT-M can be used to identify approximately 2,000 inherited single gene disorders with high accuracy.
Who can benefit from it?
- Couples with a family history of a serious disease concerned about passing it on to their offspring.
- PGT-M tests for diseases such as single gene disorders including cystic fibrosis and sickle cell anaemia, sex-linked disorders including Fragile X syndrome and Duchenne muscular dystrophy as well as thalassemia.
- Parents may also use PGT-M to find matching stem cells for other siblings in need of a bone marrow transplant.
- In some countries such as Thailand, couples may use PGT-M to select the gender of their baby.
How is it performed?
- An embryo biopsy is performed whereby approx. 3-8 cells are removed from each day 5 embryo (a blastocyst) and the cells are sent to a lab for testing.
- The embryos are then frozen and transferred later if they are come back normal.
PGT-SR for Chromosomal Structural Rearrangements
What is it?
PGT-SR looks for a balanced chromosomal translocation which occurs when either a) 2 segments of different chromosomes break off and swap places (Reciprocal Translocations); or b) two chromosomes join (Robertsonian Translocations); or c) when a segment of a chromosome is flipped upside down (Inversions).
Who can benefit from it?
- Couples with chromosomal translocations (one party or both)
- Couples who have had two or more unexplained miscarriages
How is it performed?
NGS-SR
NGS is performed to analyse for a balanced set of all 23 pairs of chromosomes. Then a balanced embryo can be transferred.
Karyomapping
This latest technology is used where couples want to check embryos for carrier or non-carrier translocations, and only transfer non-carriers if available.
If you have any questions, feel free to email me at lovehopejabsandprobes@gmail.com.
Sources:
https://thaisuperiorart.com/
https://www.arcfertility.com/ivf-pgd-pgs-genetic-testing-can-tell-embryo/
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